In May, four British men climbed Mount Everest in an ultra-rapid expedition that took them from London to the summit and back in less than a week. The trip was organized by Lukas Furtenbach, an accomplished and sometimes controversial guide from Austria who has long sought to speed up Everest trips from their typical six- to eight-week duration. The breakthrough in this yearā€™s expedition, according to media reports, was that the men inhaled xenon gas two weeks before they left in order to prepare their bodies for the rigors of high altitude.

The news prompted a flood of criticism, much of it focused on ethics and mountaineering culture. ā€œWhy not just fly up there in a helicopter and touch the top so you said you did it?ā€ the American guide Garrett Madison asked. Those criticisms take for granted that xenon actually worksā€”but scientists arenā€™t so sure. in the journal High Altitude Medicine & Biology takes a critical look at the claims and evidence for xenon as a mountaineering aid.

Why Might Xenon Help?

There are three possible ways that xenon might help you handle high altitudes: triggering artificial pre-adaptation to thin air, preventing altitude illness, and protecting your brain from damage caused by low oxygen levels. In the new paper, a team of researchers led by Andrew Luks of the University of Washingtonā€”the lead author of the Wilderness Medical Societyā€™s on prevention and treatment of altitude illness, as it happensā€”evaluates each of these claims.

The main reason conventional Everest expeditions are so long is that your body gradually adapts to breathing air with lower levels of oxygen. Many of the changes are triggered by a set of proteins called ā€œhypoxia-inducible factors,ā€ or HIFs, which sense oxygen levels and whose discovery earned the . One of the key changes is an increase in EPO, which triggers the production of red blood cells that ferry more oxygen from the lungs to the rest of the body.

There is indeed evidence that inhaling xenon can increase the activity of HIFs, and consequently increase levels of EPO in the blood. In , inhaling xenon for just two minutes increased EPO levels for up to eight days, albeit with plenty of variability between subjects. But this increase didnā€™t translate into any measurable increase in red blood cells or improvement in performance. Luks and his colleagues find it implausible that this slight bump in EPO would have any noticeable effect on altitude acclimatization.

The case for preventing altitude illness is even shakier. There are three main types: acute mountain sickness, which is the mildest and most common form and whose defining feature is headaches; high-altitude cerebral edema, which involves swelling in the brain; and high-altitude pulmonary edema, which involves swelling in the lungs. The last two are potentially fatal. There are no studies directly testing the idea that xenon prevents these conditions and no convincing theoretical reasons to think it should. And most importantly, given that the gas only stays in your body for a matter of hours, itā€™s unlikely that any hypothetical protective effect would still be there two weeks after you inhale the gas.

The idea of ā€œneuroprotectionā€ is the most intriguing. There have been a few studies in animals suggesting that taking xenon can help protect the brain from the injuries that occur when the flow of blood to the brain is suddenly stopped, like in a stroke, heart attack, or traumatic brain injury.

Leaving aside the question of whether those studies can be extrapolated to humans, Luksā€™s bigger objection to this claim is that stopping blood flow to the brain (as in, say, a stroke) is very different from the situation at altitude, where blood flow stays the same or even increases but the blood contains less oxygen. In the former case, physical damage is often caused when blood suddenly starts flowing again; in the latter case, the blood never stops flowing.

How Did They Climb Everest So Quickly, Then?

The fact remains that the British climbers really did summit in less than a week. Luks and his colleagues attribute that success to two more mundane factors. First, the climbers reportedly spent ten weeks before the expedition sleeping in altitude tents at simulated elevations of up to 23,000 feet (compared to Everestā€™s peak of just over 29,000 feet). Thereā€™s plenty of evidence that this really does trigger adaptations, for example enabling you to maintain higher levels of oxygen in your blood once you begin climbing and reducing the risk of altitude illness. Furtenbach has been using this technique with clients since 2017 for three-week Everest climbs.

The other aid is the generous use of supplemental oxygen while climbing. On the three-week expeditions, Furtenbachā€™s clients are each accompanied by two sherpas, so they have the capacity to carry plenty of spare oxygen. Hereā€™s a chart showing the effective altitude based on levels of blood oxygen (SpO2), as a function of how much oxygen you flow through your breathing mask:

Using one liter of oxygen per minute drops the effective altitude from 8,848 to 7,185 meters; using two liters drops is to 4,489 meters, which is already below the elevation of base camp. These numbers assume youā€™re at rest; you need to inhale more oxygen to maintain your blood levels if youā€™re exercising. For example, doing light exercise while getting two liters per minute of oxygen bumps the effective altitude back up to 6,442 meters. The solution? Turn the oxygen up even higher. Furtenbachā€™s website promises ā€œunlimited oxygenā€ with equipment capable of delivering up to eight liters per minute.

To Luks and his colleagues, these two factorsā€”pre-acclimatization in altitude tents, then high levels of oxygen flowā€”are enough to explain how the one-week expedition succeeded. If thatā€™s the case, it seems surprising that others havenā€™t tried the same thing. But perhaps itā€™s more a question of risk tolerance rather than technological breakthroughs.

Whatā€™s the Verdict?

Itā€™s quite clear that xenon has not been shown to make Everest expeditions safer or fasterā€”yet. I suspect even Furtenbach might acknowledge that heā€™s operating for now in the realm of scientific extrapolation and personal experimentation.

Whatā€™s more debatable is whether the idea is probable, or even plausible. To Luks, itā€™s not just that weā€™re waiting for better evidence. ā€œMy bet is that if those studies are done,ā€ he told me, ā€œit will show that xenon »å“Ē±š²õ²Ōā€™t do anything.ā€ Benjamin Levine, a prominent sports scientist at UT Southwestern Medical Center who led the definitive 2019 study of xenonā€™s effects of EPO and blood levels that I mentioned above, is similarly skeptical. ā€œThere is not only no evidence, but no rationale for why xenon would work in this setting,ā€ he says.

Levine worries that all the speculation about what xenon might (but probably »å“Ē±š²õ²Ōā€™t) do will lead others to begin experimenting with it. Similar to the recent controversy about athletes using carbon monoxide to boost performance, xenon also carries potentially serious risks. ā€œWe know for sure that xenon can hurt people,ā€ he told me.Ā ā€œIn our studies, we gave it with full support of a cardiac anesthesiologist, and still had some volunteers lose awareness and near loss of consciousness. Doing it in someoneā€™s garage without medical support will for sure lead to a catastrophic outcome for somebody.ā€

The other risk, according to Luks, is that if you head to high altitude relying on the magic of xenon and copious supplemental oxygen to protect you, youā€™ll be in big trouble if, say, youā€™re pinned down by bad weather long enough that your oxygen runs low, or if something else goes wrong with your oxygen supply. The usual practice of spending weeks acclimating to the mountain will help protect you, at least temporarily, in that situation.

Of course, this last objection applies even if youā€™re not using xenon. Everyone who ventures to the summit of Everest while relying on oxygen faces an existential risk if the oxygen runs out. Iā€™m pretty sure that this yearā€™s controversy will spark a bunch of studies on xenonā€™s potential benefits for mountaineering. Iā€™ll be curious to see what they find. But whatever the results, no lab studies will resolve the deeper philosophical debate about what risks are worth running to summit a mountain, what forms of aid are fair game, and what the whole enterprise is really about.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post They Said Xenon Helped Them Set a Record on Everest. Now Scientists Are Questioning If It Really Had an Impact. appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

On the fifth day, a dead seal washes up on the beach in front of where weā€™ve pitched our tent. Weā€™re on a remote and beautiful stretch of coast called Nissen Bight, at the extreme northwest tip of Vancouver Island, surrounded by roadless wilderness where no one lives and few people visit. Itā€™s so wild that three of the first four seasons of the History Channelā€™s survival show Alone were filmed near here. In fact, thatā€™s part of the reason we came. Weā€™re big fans of the show and love imagining how we would fare.

The hike so far has been brutally hard. Along with my wife, Lauren, and our kids, Ella and Natalie, Iā€™m following the , a roughly 37-mile path along the top of the island. Itā€™s the newer and lesser-known partner of the , Canadaā€™s most famous backpacking route, which is more easily accessible, more carefully maintained, and so popular that access is carefully rationed with advance bookings. About 7,500 people hike the West Coast Trail each year, which is roughly how many people have ever completed the North Coast Trail since opened in 2008. A grizzled hiker we met a few days earlier tells us that the northern trail reminds him of how the West Coast Trail was when he first hiked it in 1975.

In Alone: Frozen, a 2022 spin-off season set in Labrador, one of the contestants finds a big chunk of seal skin washed up on the beach. ā€œI mean, it smells fresh,ā€ she says. ā€œSeal fat soup, thatā€™s whatā€™s for dinner tonight.ā€ This scene is on all of our minds as we contemplate the dead seal on Nissen Bight. My main worry is that the carcass will attract wolves or cougars or bears if it stays there overnight. But I also have a moment of perfect clarity and self-knowledge: out here in the wilderness, hundreds of miles from the nearest store, where nature is still red in tooth and claw, thereā€™s still no way in hell Iā€™d eat that seal.

Here are five other insights I took away from the trip, which Iā€™ll try to keep in mind as I await details on Season 13.

1. The Terrain Is Insane

How hard, you ask, could a 37-mile hike be? We gave ourselves six days to cover the distance, which meant that we averaged around five miles in eight hours on each of the first five days, then put in a big final day when the terrain got easier. It alternates between steep, muddy rainforest and rocky beaches and headlands. The mud can be thigh-deep or worse; the scrambles up and over vertical headlands, sometimes assisted by a greasy rope, are exhausting and sometimes terrifying. And this is on the trail!

In Season 4 of Alone, pairs of participants were dropped roughly ten miles apart and had to reunite by bushwacking through the forest. It took eight days for the first pair to reconnect, which struck me at the time as ridiculous. After hiking in the area, Iā€™m now flabbergasted that they managed to get anywhere at all. Never was this more clear than when we received satellite warning of a potential tsunami one evening and had to contemplate fleeing from the coast. The obvious response would have been to hike inland and uphill through the woodsā€”but without a trail to follow, that option seemed all but physically impossible.

2. The Wildlife Is Wild

Iā€™ll admit that Iā€™ve snickered when Alone contestants tap out after hearing or seeing a bear. In Season 1, someone taps out after the first night because a bear was sniffing around his camp. The bears on Vancouver Island are almost exclusively black bears rather than grizzlies, so the danger »å“Ē±š²õ²Ōā€™t seem extreme to me. Still, I realize things can hit differently when youā€™re truly in the wild rather than, say, in a national park with help nearby.

Itā€™s not just bears. The northern part of Vancouver Island reportedly has the highest concentration of cougars on the planet, along with hundreds of wolves. We didnā€™t see any cougarsā€”although that »å“Ē±š²õ²Ōā€™t mean they didnā€™t see usā€”but we saw plenty of wolf tracks, including fresh ones one morning showing that they had passed right through our camp overnight.

And sure enough, a bear strolled out of the woods one evening a few hundred yards from our tent and wandered down to the shore. We unsheathed our cans of bear spray and settled in to watch. It looked like the bear was munching on the thick bed of half-dried seaweed just above the waterline (probably, , foraging for tiny crustaceans hidden within). We watched for half an hour, and eventually tired of the show, but the bear foraged on. We headed off to cook and eat dinner, then got in the tent and zipped into our sleeping bags while the bear kept munching. It was gone by morning.

3. The Ocean (in Theory) Provides

The jumping-off point for our hike (and for the initial seasons of Alone) was a town called Port Hardy, a six-hour drive north from Victoria, where the islandā€™s main airport is located. From there, itā€™s an hour-long water taxi ride along the coast to the start of the North Coast Trail. During the ride, we saw humpback whales, orcas, seals, sea otters, and waves of the pink salmon that were running during our visit in early August. During the hike, too, we got used to watching seals and sea otters (and often, we eventually realized, pieces of driftwood) playing in the waves just offshore.

We spent our second night on a beach at Cape Sutil, where thereā€™s also a nearby yurt where park rangers sometimes camp during the hiking season. There were three rangers there that evening, and one of them wandered down to the beach with his fishing rod and pulled out a giant pink salmon on one of his first casts. We tried to look hungry, but it turned out that the rangers had a propane freezer to store whatever they didnā€™t eat for dinner.

It was one of those moments that lures you into thinking that it wouldnā€™t be so hard to feed yourself out there. But the ranger had high-quality fishing gear, as opposed to the jury-rigged rods and line Alone contestants have to rely on. He and his two colleagues then spent another hour or so fishing up and down the beach with no further luck other than a couple of small ones they threw back. As much as I like to imagine feasting on salmon, a more realistic fantasy is probably the disgusting worm-like gunnels that Ted and Jim Baird harvest from under rocks in the intertidal zone in Season 4. ā€œIf you havenā€™t realized,ā€ Ted says at one point, ā€œitā€™s foraging that wins this show.ā€

4. Things Can Go Wrong

On our second-last day of hiking, we caught up with a woman hobbling along the trail using her hiking poles as crutches. She had slipped and wrenched her knee badly, but there were no easy extraction points nearby, so she was trying to hike another ten miles out while her uncle carried her pack along with his own. I offered to haul her pack another mile up the trail, but there wasnā€™t much else we could do.

The various seasons of Alone are rife with accidents of varying types and levels of severity: falls, burns, blade wounds, poisonings, and so on. This is a risk in any backcountry endeavor, of course. But the slippery, jagged terrain on Vancouver Island felt unusually treacherous to me, especially with a heavy pack interfering with my balance and steadily mounting fatigue in my legs and mind. We were only hiking for a week, and we werenā€™t starving. If weā€™d been out longer, it would have been only a matter of time before we had a mishap.

5. The Feeling of Being Alone Is Awesome

We werenā€™t actually alone on the North Coast Trail. At every place we camped, there was at least one other tent somewhere nearby. Thatā€™s not because the trail is crowded, but rather because there are so few places along the route that have access to drinking water and a flat place to pitch a tent. That explains why Alone contestants sometimes struggle for days to decide where to make their camp, and it also explains why the few backpackers on the North Coast Trail usually end up clustering at the same overnight spots. But hey, we felt alone!

In Alone: Frozen, all the contestants were show veterans who had notched long stays on previous seasons, so it was surprising to see several tap out really earlyā€”in one case after just five days. ā€œThere was PTSD in my body,ā€ the eventual winner, Woniya Thibault, told ¹ś²ś³Ō¹ĻŗŚĮĻ last year. ā€œI didnā€™t think of my first season as traumatic, but then you get back out in the wilderness and you realize it was actually really hard.ā€ Going backpacking in the same terrain gave me a glimpseā€”a faint one!ā€”of just how hard it must be. But it also reminded me why people are drawn to these places, even without prize money or glory on the line. Itā€™s a magical feeling.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post What an ā€˜Aloneā€™ Fan Learned Backpacking in ā€˜Aloneā€™ Country appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

Running is a spring-loaded sportā€”and no, I’m not just referring to the springy, carbon-plated super shoes that have swept the running world in recent years. Muscles and tendons themselves act like elastic bands, stretching with each stride and then springing back to help power the next. By some estimates, this recoil cycle provides about half the energy required for sustained running, meaning that the elasticity of your muscles is just as important as more commonly discussed parameters like VOā‚‚ max. The problem: over the course of a long, hard run, the elastic starts to wear out.

Earlier this year, scientists from the Nike Sport Research Lab in Oregon published the first data on muscle elasticity in runners before and after a marathon. The results suggest a link between the elasticity of your quads and their ability to resist muscle damage, which is a crucialā€”perhaps even the most crucialā€”limitation to marathon running. The repetitive trauma of tens of thousands of steps causes microscopic damage to the muscle fibers in your legs, and has found that this damage is the best predictor of how much you’ll fade late in the raceā€”better even than fueling status, dehydration, or core temperature. So, how can you protect yourself against muscle damage during a race? By altering your muscle elasticity.

The link between the two has only recently been established, thanks to a relatively new technique called shear-wave elastography. By sending an ultrasound wave into the muscle and calculating how fast that wave travels, researchers can estimate the muscle’s elasticity. Specifically, they use a parameter called the elastic modulusā€”a material property like density or thermal conductivityā€”that tells you how much the muscle stretches when you pull it with a given force. It turns out that this elastic modulus is : the microtraumas that accumulate during a marathon cause the muscle to stiffen by the end of the race. And your baseline level of elasticity before the starting gun also matters, because springier muscles can likely absorb more footstrikes before they start to get damaged.

The new Nike study aimed to test this proposition. The lead author was Brett Kirby, one of the scientists behind the company’s Breaking2 marathon project with Eliud Kipchoge back in 2017, and the in the European Journal of Applied Physiology. Kirby and his colleagues used shear-wave elastography to measure quad elasticity in eighty runners before and after the Chicago and Boston marathons. As expected, they found that faster and more experienced runners tended to start with a lower elastic modulus, corresponding to springier muscles, presumably because their legs had adapted to higher levels of training. The researchers also found that running a marathon made the muscles stiffer and harder to stretch, increasing elastic modulus by about 23 percent from start to finishā€”a red flag indicating accumulated muscle damage.

The researchers checked in with the runners 24, 48, and 72 hours after the race to assess soreness and what pace they figured they could run for two miles. Only about a third were recovered after 72 hours, and there was a clear link between elasticity changes and how long they needed to recover. The bigger the increase in elastic modulusā€”a proxy for muscle damageā€”during the race, the longer the runners needed before they could run normally again.

On the surface, this might seem obvious: the more you trash your legs, the longer it takes to recover. But connecting muscle damage to elasticity gives us a new lens to explore ways of reducing that damage. Nike is a shoe company, so you can guess what they were most curious about. The defining feature of the current generation of super shoes, along with the carbon-fiber plate, is a thick layer of light, bouncy midsole foam. Might this pillow of cushioning absorb some of the impacts of running, sparing the elasticity of the quad muscles? In a word, yes. Thirty-three of the 80 runners in Kirby’s group were wearing super shoes, and their elastic modulus increased by only 17 percent from marathon start to finish, compared to 31 percent in a speed-matched group wearing regular shoes. The big selling point of super shoes is that they enable you to run more efficiently as soon as you put them on. But these findings suggest they may also keep you on pace in the late miles of a marathon, and enable you to rack up more training week after week without trashing your legs.

There are other ways to improve elasticity and therefore harden your legs against muscle damage. The traditional advice includes training strategies like high mileage, long marathon-pace runs of up to 20 miles, downhill running, and lifting heavy weights. With shear-wave elastography, we now have a tool for testing how well each of these approaches works. For example, simply stretching your muscles seems to produce mixed results, which isn’t surprising; repeatedly pulling on an elastic band doesn’t make it springier. On the other hand, that eight weeks of drop-jump workouts reduced calf muscle elastic modulus by 21 percent.

For now, though, the most compelling anti-muscle-damage data is for the shoes. That’s significant because super shoes have been enormously controversial. What does it mean for the history of the sport when virtually every record at every level is wiped from the books in the course of a few years? What does it say about the broader culture of running that so many of us are eager to shell out upward of $300 for a pair of shoes that promises to slice a few minutes off our times without any additional effort on our part?

These are hard questions to grapple with, but the elasticity data validates another perspective that, until now, has been mostly anecdotal. For a lot of runners, thickly cushioned super shoes feel better to run in. During and after races and training runs, they claim their legs feel less beat-up, and they’re quicker to bounce back for the next run. As someone who’s been running for more than three decades and hopes to keep running for at least three more, racing a tiny bit faster may have no grand cosmic meaningā€”but being able to walk down the stairs the morning after a marathon, or simply feeling fresh the day after a long run in the mountains? That’s a promise that puts a spring in my step.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post How Muscle Elasticity Affects Performance and Recovery appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

At a conference earlier this summer, a research team from Inova Schar Cancer Institute in Virginia presented on colon cancer in runners. Out of 100 marathoners and ultramarathoners between the ages of 35 and 50 who underwent colonoscopies, 42 had polyps, or which 15 were considered advanced pre-cancerous growths. These are bigger numbers than youā€™d expect, and the New York Timesā€™s on the research has sparked a wave of concern.

Iā€™m not here to dismiss those concerns. Admittedly, as a runner and running journalist, I hope the current version of the story turns out to be wrong. And itā€™s easy to poke holes in studies whose results you donā€™t like: this one »å“Ē±š²õ²Ōā€™t have a control group, for example, and hasnā€™t yet been through peer review. But what I really want is to understand whether there are genuine risks that runners need to consider, which is a question that will take further research to answer. For now, here are a few thoughts about the broader context of these findings.

Ā The Links Between Fitness and Colon Cancer

There have been plenty of previous studies on how exercise and aerobic fitness affect the risk of colon cancer. The overall conclusion is that being fitter reduces your risk.

For example, of 177,000 men found that those with the highest fitness (as assessed with an exercise test to estimate VO2 max) were least likely to develop colon cancer over the subsequent decade. Hereā€™s a graph showing their risk as a function of fitness:

You can see that the graph gets steadily lower with increasing fitness: thereā€™s no hint that it turns up for the fittest people. The highest value of VO2 max on this graph is 55 ml/min/kg, which to a marathon time of a little under three hours. These are seriously fit people, in other words.

Another study of 643,000 U.S. military veterans, in Mayo Clinic Proceedings, found a similar pattern. Those with the highest fitness were less than half as likely as the least fit subjects to develop colon cancer over time. Hereā€™s that data:

In this graph, each line shows the fraction of people who have not been diagnosed with colorectal cancer, so the higher lines have fewer cases. The ā€œhigh-fitā€ group here has aerobic fitness of 13.6 METs, on average, which corresponds to a VO2 max of about 48 ml/min/kgā€”once again a fairly impressive level of fitness.

Having a high VO2 max is partly genetic, so itā€™s also worth looking at the data on exercise habits and colon cancer risk. Once again, the relationship is pretty clear. Thereā€™s representative data in that merges data from nine previous studies with a total of 755,000 subjects. Hereā€™s the link between amount of exercise per week and risk of colon cancer:

Exercise is measured in MET-hours, which is basically multiples of your basal metabolic rate. The standard recommendation for exercise is 7.5 to 15 MET-hours per week, which corresponds to 150 to 300 minutes of moderate exercise. The highest group in this study was getting 30 MET-hours per week, or roughly 600 minutes (i.e. ten hours) of moderate exercise per week. Again, this is a pretty active group, with no sign of elevated colon cancer risk.

Defining ā€œExtremeā€ Exercise

How do we reconcile these two datasets? Thereā€™s tons of data suggesting that relatively high levels of both exercise and aerobic fitness are really good for reducing the risk of colon cancer. But perhaps the new study is testing a different group of people who are doing ā€œextremeā€ levels of exercise that arenā€™t captured in these big studies of regular people. The distinction here echoes the debate a decade ago about the potential for heart damage from excessive endurance training. Some of the initial studies claimed that running as little as 20 miles per week could cause problems, but those studies turned out to have serious statistical flaws. Instead, the ā€œextremeā€ groups sometimes involved people who had done dozens or even hundreds of ultra-endurance events.

The inclusion criteria for the new colon cancer study were that you had to have completed at least two ultramarathons of 50K or longer, or else at least five official marathons. In the running world, this wouldnā€™t qualify you as some sort of crazy fanatic, but itā€™s certainly more than casual running. Is it enough to mess up your colon? The theory seems to be that prolonged exercise can cause blood to be redirected from the colon, starving the cells there of oxygen and causing inflammation and damage.

At this point, itā€™s simply not possible to say with any confidence whether the new results signal a genuine danger, whether theyā€™re a statistical fluke, or whether thereā€™s another explanationā€”that the people who volunteered for the colon cancer study tended to be people who had already noticed something strange in their bowel health, for example. The findings should generate a wave of new studies that will help us figure out whatā€™s going on.

But itā€™s worth considering what we would do if the results do hold up to scrutiny. There are two points that I think are important to consider. One is that the choice of whether and how much to run is a holistic one: you make it based not just on what it does to your colon, but what it does to your heart and lungs and mind and so on. The overall health risks of running pale in comparison to the risks of not exercising. The second point is that, in the meantime, you should take those potential risks seriously. The American Cancer Society regular screening for colon cancer beginning at age 45.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post What You Need to Know About the New Data Linking Marathons to Colon Cancer appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

The logical response to a bad race is simple: train harder. Whatever youā€™ve been doing didnā€™t get you the results you wanted, so you need to dial up the intensity to salvage your racing season. Pain is just weakness leaving the body, and youā€™ve been weak.

As seductive as this logic is, the data in suggests that itā€™s wrong. Sports scientists in the Netherlands analyzed training and racing data from a professional cycling team on the womenā€™s World Tour, trying to pick out the training patterns associated with ā€œhighly successfulā€ and ā€œless successfulā€ racing seasons for individual riders. The key to success, it appeared, wasnā€™t more hard ridingā€”it was more easy riding, a conclusion that dovetails with some of the biggest trends in endurance training.

The study was led by Annemiek Roete and Robert Lamberts of the University of Groningen, and included data from 14 cyclists over a total of 43 seasons between 2013 and 2019. In 18 of those seasons, the riders averaged at least 5 points per race, according to the website ProCyclingStats, which roughly corresponds to being in the top 15 percent the peloton. These seasons were labeled ā€œhighly successful,ā€ while the other 25 seasons were labeled ā€œless successful.ā€

The researchers had access to comprehensive training data from those seasons: how long and far the cyclists rode, their power output, heart rate, perceived exertion, and more. From this data, the amount of time they spent in various intensity zones (calculated based on either power output or heart rate) could be calculated.

Hereā€™s the key data, showing how much time the riders spend in six zones of power output over the course of the full training season:

The most obvious difference is that the cyclists trained more during the highly successful seasons, racking up a total of 563 hours compared to 443 hours in less successful seasons. Their average rides were both longer (2.6 vs. 2.3 hours) and farther (47 vs. 42 miles), but the average power was basically the same (130 vs. 131 watts).

Where did all this extra training happen? In zones 1 and 2, which correspond to less than 55 and less than 75 percent of , a threshold concept thatā€™s widely used in cycling and corresponds to the average power you could sustain for an hour. In other words, the riders did more easy riding in their best seasons, but roughly the same amount of harder riding. This fits nicely with the longstanding idea of polarized training, which is sometimes summed up with the rule of thumb that 80 percent of your training should be relatively easy and just 20 percent hard. You could argue that it also fits with the more recent popularity of Norwegian threshold training, which also tends to avoid the upper intensity zones.

The heart rate data backs up this interpretation. During highly successful seasons, the riders averaged 126 beats per minute, or 64 percent of max. In the less successful seasons, it was 132, or 67 percent of max. This is consistent with the idea that the riders were racking up more easy riding, and thus bringing their overall average heart rate down, during the better seasons.

Taken together, these findings echo an analysis I wrote about last year of a very different dataset. Researchers crunched 16 weeks of Strava data from 120,000 runners leading up to marathons that they ran in anywhere from sub-2:30 to 6:30. This encompasses widely varying populations of runners, but the key difference was the same as in Roete and Lambertsā€™s data: the faster marathoners did significantly more easy running than the slower runners, but similar amounts of medium and hard running.

One problem with the marathon data is that you donā€™t know which direction the arrow of causality is pointing. Does more slow training make you faster? Or do fast runners have an easier time accumulating more slow training? The cycling data is a little stronger because it includes an average of three seasons from each cyclist, so it suggests that the same cyclist gets faster when they do more easy training.

So does this mean that, instead of hammering your next workout, the best response to a bad race is to start racking up more easy miles? Iā€™d be cautious about jumping in too enthusiastically. Even easy miles put stress on your body, so any changes in training should be gradual and titrated according to your ability to recover between workouts. But in the long term, evidence is mounting that the shift away from gut-busting hero workouts and towards what used to be called LSDā€”thatā€™s long, slow distanceā€”is a smart one.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post New Evidence That Long, Slow Distance Is the Key to Endurance Success appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

Shortly after sundown on July 29, I found myself on a stony beach at the extreme northern end of Vancouver Island, holding my phone above my head and pointing at an indeterminate point in the sky. Around me, three other people were doing the same thing. One of them had just been alerted via satellite message that a massive earthquake off the coast of Russia had triggered for the entire west coast of the island. Now we were frantically trying to determine whether we needed to abandon our tents and flee into the rainforest.

Last fall, Apple debuted a new feature on its most recent phones (iPhone 14 and later): when you have no cellular coverage, you can send iMessages and regular text messages via Globalstarā€™s constellation of 25 satellites. I was already planning my familyā€™s seven-day hike along Vancouver Islandā€™s North Coast Trail for the summer of 2025, and intended to buy a Garmin inReach for emergency communications via satellite. But Appleā€™s announcement made me reconsider. In June, I swapped my old iPhone XS for a new iPhone 16 specifically to get satellite messaging for a couple of backcountry trips this summer. Hereā€™s how it went.

Getting Connected

My biggest worry was that Iā€™d get into the wilderness and then discover that the feature didnā€™t work as expected. Thereā€™s been plenty of online chatter about whether the iPhoneā€™s satellite functionality might be a suitable replacement for dedicated satellite messengers, but very few first-hand reports.

You canā€™t send satellite messages when you have cellular coverage, but there is a feature that enables you to practice connecting to a satellite. Open Control Center by swiping down from the top right, tap the cellular icon on the righthand margin, choose Satellite then Try Demo (further instructions ). Youā€™ll end up with a picture of the globe with a satellite in the sky above, showing you which direction to point the phone, or else a message telling you how long until the next satellite is available. It’ll tell you when youā€™re successfully connected. Doing that a few times before I left on the trip reassured me that I knew what to do.

Once I was actually off the cellular grid, the process was even easier. As soon as you open the Messages app, the phone asks whether youā€™d like to connect to a satellite, and a Satellite menu appears in the Settings app below Wi-Fi, Bluetooth, and Cellular.

There are various about who exactly can receive messages from youā€”to receive satellite iMessages, your contact needs at least iOS18. Anyone with a non-Apple phone (or an iPhone with iOS 17.6 and up) can receive regular SMS texts. For backcountry safety purposes, I donā€™t really care whether I can send emojis, so SMS is fine. There is one important note: you wonā€™t receive messages from other people via satellite unless youā€™ve already sent them a satellite message or if theyā€™re listed among your emergency contacts (which, strangely, ). This is something thatā€™s definitely worth doing before you leave on a trip, so that your loved ones can send you, say, unexpected tsunami warnings.

I played around with satellite messages after dinner on our first night hiking on Vancouver Island, and successfully sent and received messages with various people on new and old iPhones as well as Android phones. Sending a message takes about 30 seconds, but replies came promptly. You need a clear view of the sky, which was easy at beach campsites but tricky when hiking through dense forest.

Comparing to the Competition

Iā€™ve used a wide variety of emergency communication devices over the years. The simplest is a personal locator beacon: you press a button, and it starts broadcasting your location to emergency rescue teams. Thatā€™s great as a last resort, but lacks nuance.

On one year, we reached our designated float plane pick-up spot only to find a forest fire burning on the banks of the river. A personal locator beacon wouldnā€™t have helped us much. Fortunately, we had a satellite phone, so we were able to speak to the pilot, who reassured us that the fire had been burning slowly for a week, and we could safely camp there for the night. Then a storm rolled in and prevented the plane from flying, leaving us stranded on the river for an extra day and night with a few sausage ends and some bannock to sustain us. We were very glad to have the sat phone for updates.

In recent years, weā€™ve started to use a friendā€™s Garmin inReach on trips. Itā€™s been a great intermediate option, with two-way communications at a better price point. The inReach is rugged, has great battery life, and also provides weather forecasts. I was a convert, until the option of using my phone arose.

The iPhone definitely isnā€™t a perfect substitute for an inReach or other dedicated satellite messengers from companies like Spot, Motorola, and Zoleo. Itā€™s less rugged, and has far less battery lifeā€”especially if, like me, youā€™re also using the phone as your primary camera. I brought a 10,000 mAh power bank with me, which should give me about three full recharges. In the end, by keeping the phone in power-saving and airplane modes, I only had to recharge it once over the course of seven days.

The satellite coverage also isnā€™t as comprehensive. The gold standard here is the Iridium network, which has 66 active satellites and is what the inReach uses. An Apple spokesperson told me that the Apple satellite service is only available in the United States, Canada, and Mexico. The companyā€™s support pages also that it might not work above 62 degrees latitude, which includes the northern parts of Alaska.

The Verdict

For my purposes, as a recreational-but-not-too-extreme backcountry tripper, the iPhone does the job. The biggest advantages for me are eliminating an extra device to carry, and the price: satellite messaging is free for two years after the activation of the phone. Apple hasnā€™t yet announced what the pricing will be after that. To be honest, I hope itā€™s not too cheap, or at the very least not free.

Back in 2013, when the inReach was new, I wrote lamenting the demise of blank spots on the communications grid. One of the great joys of my backcountry trips is seeing that last bar of cellular service disappear, and knowing that the outside world no longer has its tentacles around me. The safety benefits of satellite messaging are so clear that I canā€™t convince myself not to take a device with me. But I still resent the connectivity. Thatā€™s why I hope thereā€™s at least a nominal price barrier that will help me limit my own use of satellite messaging to important situations, rather than spending my evenings around the campfire responding to idle banter from friends back in the city.

You could even argue that my hike on Vancouver Island would have been more peaceful if none of us had ever received that tsunami alert. It was late in the evening, long after my friends and family back on the east coast had gone to bed, so I struggled to get updates. Eventually, one of the other people camping on the beach managed to reach a friend who reported back that the size of the wave was expected to be less than a foot. A few people who had set up on the beach itself moved their tents up into the forest, where my tent was already set up.

The trade-offs remind me of the debate about early medical screening tests: you get advance warning of possible problems, but the price you pay is a bunch of false alarms. I was glad to have satellite connectivity on my trip, and Iā€™ll keep using it on future trips. But when I went back to my tent that night, after reassuring my kids that we were going to be OK, I turned my phone off before going to sleep.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post How My iPhoneā€™s New Satellite Messaging Function Kept Me Connected in the Backcountry appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

Itā€™s hard to claim that collagen is a ā€œhot new supplement,ā€ given that its health benefits were already being promoted by the twelfth-century Benedictine abbess . In its modern form, collagen supplements have been hyped for decades for purposes ranging from joint pain to hair thickness, despite a general lack of convincing evidence that they work. But interest has spiked over the past few years thanks to a burst of new research, and the latest study on the topic bolsters the claim that collagen might help build springier tendons and muscles to enhance explosive strength.

Why Collagen Might Help

I first wrote about the new wave of collagen research back in 2019, and followed up with more in 2023. The traditional view is that collagen-rich connective tissues such as tendons, ligaments, and cartilage are effectively inert, with very limited ability to grow or repair themselves after injury. What collagen proponents argue is that taking collagen supplements supplies the key building blocksā€”for example, an amino acid called prolineā€”that trigger the synthesis of new connective tissue in the body.

The skeptical view is that collagen supplements are broken up into their constituent amino acids when you digest them, just like any other form of protein. As a result, theyā€™re no more effective for building collagen in the body that, say, drinking a glass of milk (which also contains proline). There is, however, a bit of evidence that some collagen-specific peptidesā€”short chains of amino acidsā€”make it through the digestion process intact and show up in the bloodstream.

The evidence for these claims and counterclaims has been decidedly mixed. Part of the problem is that most of the studies use some combination of collagen and specific exercise protocols in an attempt to maximize the benefits, in the same way that protein supplements are most effective for building muscle when combined with strength training. This is a good idea, but it makes it tricky to interpret conflicting results. Did the study fail because collagen »å“Ē±š²õ²Ōā€™t work, or because the exercise protocol was too easy or too hard, or too weird?

The New Study

comes from researchers at Japanā€™s Juntendo Universityā€”working, it should be noted, with scientists from Morinaga & Co., which manufactures and sells health and sports ā€œfood products.ā€ Their goal was to simplify the picture by studying the effects of 16 weeks of daily ten-gram collagen peptide supplements, with no other changes in exercise or diet. They recruited 50 volunteers, half of whom got the supplement while the other half got a placebo.

The specific hypothesis the researchers wanted to test was that collagen supplements would make tendons and muscles ā€œstiffer,ā€ in the sense that a stiff elastic band takes more force to stretch. This is what youā€™d expect if the collagen supplements trigger extra collagen formation in the tendons, which are primarily made of collagen fibers, and in the ā€œextracellular matrixā€ that provides structural support to muscles.

Stiffer muscles and tendons should allow you to transfer force more efficiently from your muscles to your bones, making it possible to deliver force more rapidly. Youā€™re not getting stronger, but youā€™re getting more explosive. This sort of explosive power is crucial both for athletic performance and for activities of daily living like getting out of a chairā€”and (as I wrote last fall) is also what we tend to lose most rapidly as we age.

What They Found

The results, which were published in Medicine & Science in Sports & Exercise, mostly support this hypothesis. They used MRI to measure the size of the Achilles tendon and part of the calf muscle; an ultrasound technique to measure the stiffness of the tendon and muscle; and a set of strength and power tests to see the functional effects of the supplementation.

Neither the tendon nor the muscle got any bigger, and the maximum calf strength didnā€™t change. But the elastic stiffness of both muscle and tendon increased in the collagen group, while staying unchanged in the placebo group. Here, for example, is the stiffness (as measured by how fast an ultrasound wave travels) for the collagen and placebo groups:

Perhaps more importantly, the collagen group also saw an increase in ā€œrate of torque development,ā€ which is a measure of explosive strength that quantifies how quickly you can apply force:

The final piece of the picture is that, for individual subjects, those who saw the biggest increases in muscle stiffness tended to see the biggest increases in explosive force. There wasnā€™t a clear connection between increases in tendon stiffness and increases in explosive force, but overall, the results support the chain of logic: more collagen -> stiffer muscles and tendons -> more explosive force.

What the Results Mean

You can make a much bigger argument on the basis of these results. Maybe you donā€™t care about tendons and explosive strength (though, honestly, you should). But if these results are true, then it suggests that there is something special about eating collagenā€”that itā€™s not just broken down into a potpourri of loose amino acids, and that it can trigger the remodelling of cartilage-based tissues. Maybe it really will thicken your hair; maybe it will repair your joints; maybe it will accelerate your recovery from ligament injuries.

These are big and as-yet-unproven claims, but if collagen works for tendon stiffness, then the other claims become a bit more plausible, at least in theory. I remain skeptical but intrigued. Given the mess of conflicting results produced by previous research, a single study funded by a supplement companyā€”even with a robust sample size of 50ā€”»å“Ē±š²õ²Ōā€™t settle the question either way. But it suggests that this is a line of research thatā€™s very much worth pursuing, and that we should await further results with interest.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post How Collagen Might Boost Your Explosive Strength appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

To be a sports fan in the modern era is to be at least somewhat numb to the steady drip of doping positives. Occasionally, though, a bust is so big that it changes the trajectory of the sport. Ben Johnsonā€™s positive test in 1988 almost crushed track and field for a decade. The BALCO scandal, which in the early 2000s implicated big names like Marion Jones and Barry Bonds, brought anti-doping to pro sports leagues. Lance Armstrongā€™s demise coincided with the introduction of the ā€œbiological passport,ā€ which many observers believe has helped rein in the most flagrant forms of doping.

Now we have Ruth Chepngetich. The 30-year-old Kenyan demolished the marathon world record last fall in Chicago, her time of 2:09:56 making her the first woman under the 2:10 barrierā€¦ and the 2:11 barrier. Only two other women have even broken 2:14. It was a historic, epoch-defining performanceā€”and, as I wrote at the time, so improbable that it prompted a highly unusual storm of skepticism from commentators. Sure enough, the Athletics Integrity Unit that Chepngetich has accepted a two-year suspension after hydrochlorothiazide (HCTZ), a banned diuretic sometimes used to mask the presence of other drugs, was found in her urine.

The question is: What comes next? Will it be business as usual, as has happened in the past after notable busts like 2016 Olympic marathon champion Jemima Sumgong? Will there be a crackdown on doping, perhaps with heightened out-of-competition testing funded by the worldā€™s top marathons, or stiffer penalties for the agents, coaches, and sponsors who work with athletes who test positive? Or will Chepngetichā€™s shocking-but-not-surprising downfall simply confirm that doping is ubiquitous and unavoidableā€”and that instead of wringing our hands about it, we should start getting excited about next yearā€™s pro-doping Enhanced Games?

The Case for Business as Usual

Thereā€™s one sense in which Chepngetichā€™s positive test is, well, a positive: it demonstrates that thereā€™s no protection for even the biggest names in the sport. In the past, athletics officials at the very highest echelons of the sport have covered up doping positives for ā€”and taken bribes to do so. Chepngetichā€™s bust is a disaster for the sport, but it didnā€™t get suppressed.

Sheā€™s not the first big name to go down in recent yearsā€”in fact, sheā€™s not even the first marathon world-record holder from Kenya to go down. Wilson Kipsang, who set the menā€™s record in 2013, was sanctioned in 2020 for a series of missed tests. Middle-distance runner Asbel Kiprop, an Olympic gold medalist like Sumgong, tested positive in 2017. Three-time Boston Marathon champion Rita Jeptoo tested positive in 2014. Clearly the testing regime is working on some level, and no one is immune.

Even for those who might get away with doping, thereā€™s good evidence that they canā€™t get away with as much. Instead of just trying to catch cheaters in the act with blood or urine tests, the biological passport program takes regular tests from athletes in order to establish their personal normal values. If a test shows sudden deviations from the usual values, the athlete can be banned for doping even in the absence of a positive test for a specific drug. An analysis of performances by Russian women before and after the introduction of the biological passport in track and field in 2012 found that they got two to three percent slower, likely because they could no longer use blood doping with impunity.

Still, you can only push this logic so far. The stream of prominent doping positives means testing is working, but it also means that a lot of athletes are still cheating. Itā€™s also notable that the levels of performance in endurance sports such as cycling and running have been accelerating in recent years. In running, weā€™ve been able to blame it on supershoesā€”even though theyā€™ve been around since 2016 while performances have continued to improve. In cycling, a common explanation is super-high levels of carbohydrate during races. But itā€™s hard not to wonder whether thereā€™s a simpler and more obvious explanation.

The Case for Fighting Back

One of the curious details about Chepngetichā€™s case is that she tested positive for HCTZ. Endurance athletes typically go down for erythropoietin (EPO), which boosts the number of oxygen-carrying red blood cells in the body, or for biological passport violations related to blood doping, which involves injecting extra blood (either your own or someone elseā€™s) to get more red blood cells. These are fairly simple and widely understood forms of dopingā€”the kind of thing a lone wolf could pull off.

In contrast, HCTZ is a diuretic, which can be used to dilute urine so that other banned substances donā€™t show up in tests. My usual assumption is that these kinds of masking agents are hiding steroids or other muscle-related drugs. Thereā€™s also evidence that diuretics can affect the results of blood tests in the biological passport program, for example . But spoofing the biological passport is a far more complicated game and would suggest a much more sophisticated and systematized doping operation.

Chepngetich voluntarily accepted a provisional two-year suspension in April while the case moves forward, which suggests sheā€™s eager to get the ban over with in order to return to competition. Personally, I would hope any return to competition is contingent on a full and frank disclosure of exactly what she drugs she was taking and who helped her. This is a tricky idea to enforce, but one way or another we need to get a better window into how athletes are cheating.

There are lots of other ways we could use the Chepngetich case as a spur to ramp up the fight against dopingā€”things like making agents responsible when their athletes test positive (itā€™s notable that Chepngetichā€™s agent, Federico Rosa, also represented Sumgong, Jeptoo, and Kiprop), or getting the World Marathon Majors group to fund more out-of-competition testing before their races rather than just after the finish. The truth, though, is that these are mostly the same ideas trotted out after every doping scandal.

The Case for Surrendering

Last month, Wiredā€™s Amit Katwala the best account yet of the rise of the Enhanced Games, the drugs-permitted sports event currently slated for next May in Las Vegas. My general take on this saga has mostly been that I prefer to ignore it. Sports, to me, are (as the philosopher Bernard Suits put it) about the voluntary attempt to overcome unnecessary obstacles. Arbitrarily removing some of the obstaclesā€”by moving the start line forward, say, or by taking drugs that weā€™ve agreed not to takeā€”is simply uninteresting to me.

The problem, of course, is that not everyone agrees to avoid the drugs on the banned list. Allowing athletes to take drugs, as the Enhanced Games plans to do, would eliminate all the effort required to police this rule and return us to an even playing field. I donā€™t find the idea attractive, but Chepngetichā€™s positive makes this a good time to ask: Why not?

One of the most interesting threads in Katwalaā€™s article is how the apparent mission of the Enhanced Games has shifted over time. Initially its rallying cry was the libertarian ideal that people should be able to put whatever they want into their bodies. But now it proclaims that all participants will train under medical supervision and be rigorously tested to ensure that participants remain healthy. ā€œFar from throwing off the shackles of the World Anti Doping Agency,ā€ Kitwala points out, ā€œit seemed as if Enhanced had simply re-created it, with a slightly different red line.ā€

Implicit in this shift is the recognition that unfettered doping would be bad for your health. This is, of course, the fundamental reason that drugs are restricted in sport, but the evidence for this claim isnā€™t as crystal-clear as you might think. You simply canā€™t do the kinds of studies that would be required to prove that, say, EPO thickens your blood to the point that youā€™re more likely to die of a heart attack. EPO has long been suspected as the culprit in among young cyclists after the drug was introduced in the late 1980s, but some researchers view this claim instead as ā€œ.ā€

You can have similar debates about most other performance-enhancing drugs. Thereā€™s usually for negative health effects, but the evidence is often indirect or observational. You can make a reasonable case that, for example, testosterone therapyā€™s benefits outweigh its harms for people starting with low testosterone. As the doses get higher, that case gets harder to makeā€”but figuring out exactly where the line should be drawn is tricky. The key point, though, is that there is a line. Even the Enhanced Games is no longer calling for unlimited doping.

The Verdict

Iā€™ve always thought that one of key but underappreciated distinctions in debates about sports doping is whether you think of athletes as ā€œthemā€ or ā€œus.ā€ Most of the people Iā€™ve argued with who think that doping should be legalized view sport as a spectacle that others take part in. Why not let those people dope to the gills for our greater entertainment, as long as theyā€™re doing it by choice?

To me, though, the question always comes down what Iā€™d feel comfortable doing myself, or letting my kids do. Thereā€™s a big gulf between pro marathoners and high-school track, of courseā€”but donā€™t kid yourself that theyā€™re not connected. If the pros are doing something, then the aspiring pros will have to do it, and so will the college athletes, and so on down the line. ā€œOnce an effective technology gets adopted in a sport, it becomes tyrannical,ā€ the ethicist Thomas Murray told me when I was writing about electric brain stimulation a few years ago. ā€œYou have to use it.ā€ The same is true of drugs: if we give pro athletes the green light, weā€™re accepting their use everywhere.

Thatā€™s the unspoken truth of doping in sportā€”but as it turns out, the Enhanced Games is willing to say it out loud. Their real endgame is selling their own line of supplements, inspired by Red Bullā€™s corporate success. ā€œThey buy sporting assets to sell an energy drink,ā€ the eventā€™s founder told Kitwala. ā€œAnd so our business model is very similar.ā€ They frame this in the language of ā€œhuman enhancement,ā€ but it basically amounts to ā€œsteroids for the people!ā€

In the end, thatā€™s the argument that convinces me that itā€™s worth keeping up the fight against doping. I hope that we catchā€”or better yet, dissuadeā€”future Chepngetiches. I think that sports governing bodies should tweak their rules so that Chepngetichā€™s sub-2:10 can be erased from the record books even though it took place before her positive test. But Iā€™m mostly at peace with the idea that weā€™ll never fully win this battleā€”just as I believe that stealing should remain illegal even though weā€™ll never eradicate shoplifting. Because if we accept the alternative and decide that doping is OK, itā€™s no longer just about them; itā€™s about us.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post After the Biggest Doping Bust in Years, What’s Next? appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

Back in 2011, I went to an international conference in the Australian town of Bathurst called ā€œThe Future of Fatigue: Defining the Problem.ā€ The feeling you encounter, say, 20 miles into a marathon may seem too self-evident to require any deep explanation, but it turns out to be surprisingly difficult to pin down. In psychology, thereā€™s a widespread belief that naming your feelings can help you manage them. I was interested in the fatigue conference because I figured the same might be true for athletes: if I could understand and name what was holding me back in races, perhaps Iā€™d be better equipped to push through it.

Spoiler: the conference didnā€™t come up with any final answers. In fact, defining and explaining fatigue remains an ongoing topic of debate among sports scientists, as illustrated by in the journal Sports Medicine. A group of researchers led by Jeanne Dekerle of the University of Brighton draws on recent advances in cognitive science to propose a new way of understanding what they call ā€œexercise-induced perceived fatigue.ā€

The New Theory

Dekerleā€™s framework is based on an idea called ā€œpredictive processing,ā€ which has emerged over the past decade as a powerful grand theory of how the brain works. The basic idea is that, rather than perceiving the world based on incoming data from the senses, the brainā€™s fundamental role is to predict the world, using the senses to check and correct its predictions. Last year, I wrote a brief primer on predictive processing and speculated that we would soon see it applied to endurance sportsā€¦ and here we are.

Dekerleā€™s focus is exercise-induced perceived fatigue, and she begins by trying to specify exactly what she means by this. She »å“Ē±š²õ²Ōā€™t mean feeling sleepy, or unmotivated, or out of energy. She also »å“Ē±š²õ²Ōā€™t mean that what youā€™re doing feels too effortful to continue (a distinction that turns out to be important, and that weā€™ll come back to below). Instead, drawing on a previous definition by researcher Dominic Micklewright, she defines perceived fatigue as ā€œa feeling of diminishing capacity to cope with physical or mental stressors, either imagined or real.ā€

What gives rise to this feeling? Thereā€™s no blood test or biopsy or X-ray that can measure it. Instead, Dekerle proposes that the feeling of fatigue arises when one of the brainā€™s most important predictionsā€”that the body will remain in a state of homeostasis, with key parameters like heart rate and body temperature and blood acidity in a tightly controlled rangeā€”is violated.

Itā€™s not that the high heart rate or elevated blood acidity themselves directly cause the sense of fatigue. Itā€™s about predictions. Your brain has various ways of anticipating and adjusting to the demands of exerciseā€”of ensuring that its prediction of homeostasis remains true. For example, your heart rate will increase and your breathing will quicken before you start exercising. But eventually the brain runs out of tricks, and its predictions become increasingly at odds with reality. ā€œFatigue therefore represents a state of uncertainty,ā€ Dekerle and her colleagues write, ā€œindicative of the brainā€™s diminishing confidence in its own ability to exert control over the body.ā€

Is there any evidence that fatigue is the brainā€™s feeling that its predictions are off? In , participants moved their fingers back and forth while watching their hands on a computer screen. When the researchers introduced a slight delay in the video feed, effectively messing with the volunteersā€™ predictions of where their hands should be, their perception of muscle fatigue increased. In , injecting metabolites into the thumbs of volunteers to disrupt chemical homeostasis generated feelings of fatigue.

Why It Matters

Itā€™s a neat, albeit speculative, hypothesis. But is this perception of fatigue really what matters during exercise? Previous theories, most notably the Central Governor Model developed by researchers at the University of Cape Town and Samuele Marcoraā€™s Psychobiological Model, have tended to focus instead on effort: ā€œthe conscious sensation of how hard, heavy, and strenuous exercise is,ā€ in Marcoraā€™s words. (Another, more poetic definition he has used: ā€œthe struggle to continue against a mounting desire to stop.ā€)

One way to understand the difference between fatigue and effort is to think about what happens when you stop. Effort mostly disappears if you stop running and lie on the ground, but fatigue is still there. To Marcora, a professor at the University of Bologna, itā€™s effort that functions as the master switch, determining whether you decide to speed up, slow down, or stop. One of his studies compared effort and pain during an all-out cycling test: it was effort that maxed out when the subjects gave up, while pain was still just five out of ten on average.

There isnā€™t much research on the exact role fatigue plays during exercise. Dekerle, in an email, said there are likely several different perceptions that play a role in regulating your pace during an endurance event, including effort, fatigue, and pain. Particularly for novice exercisers, even ā€œaffective valenceā€ā€”whether theyā€™re enjoying it or notā€”likely plays a role. The dominant perception may be different for each of us, Dekerle said, and might change depending on the context or even vary across the course of an event. In my first marathon, I judged my pace based on effort for the first 20 miles, and then was limited by pain in my screaming quads for the last six.

To make things even more complicated, all these various perceptions interact with each other. Pain makes exercise less pleasant. And mounting effort might contribute to the sensation of fatigue. Marcoraā€™s main critique of the new theory is that its definition of fatigueā€”ā€œa feeling of diminishing capacity to cope with physical or mental stressorsā€ā€”is really a version of another psychological concept called self-efficacy, which is your sense of how capable you are of completing a given task. Your self-efficacy during a marathon certainly depends on your sense of effort, Marcora points out, along with other factors like motivation, how far youā€™ve come, how far you still have to go, and your prior experiences of how hard it feels to run various distances.

I realize Iā€™m getting into the weeds here (and believe me, there are a lot more weeds that Iā€™m glossing over). What we feel during marathons is one of those questions that only feels obvious if you donā€™t think too hard about it. Part of me feels that itā€™s a useful rabbit-hole to go down. For new runners, I think the bombardment of sensory overload can be overwhelming, and they often slow down before they really need to. Understanding the difference between, say, effort (ā€œitā€™s hardā€) and discomfort (ā€œit hurtsā€)ā€”between warning lights and stop signsā€”can free you to push harder for longer.

On the other hand, Iā€™m also conscious of the potential pitfalls of overthinking it. After all, the idea that naming your feelings can help you manage them isnā€™t universally accepted. In one at Harvard a few years ago, naming emotions while viewing unpleasant images actually made it harder to get rid of those emotions. Iā€™m fascinated by the research of Dekerle and others who are trying to unravel the mysteries of fatigue, and hope the field continues to progress. But for now, while Iā€™m out running, Iā€™ll try to put all that terminology out of my mind and just focus on boosting self-efficacy by embracing my inner cheerleader.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post A New Theory Explains Why Exercise Makes Us Tired appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.

The most famous in music involves a lost tourist in Manhattan who asks a passing musician how to get to Carnegie Hall. The reply: ā€œPractice, practice, practice.ā€ This quip popped to mind when I was reading a new study about the caloric requirements of 100-mile mountain ultramarathons. Youā€™ll burn something like 16,000 calories during one of these races, which is an amazing numberā€”but it takes more than calories to reach the finish line.

The , which appears in the International Journal of Sports Physiology and Performance, dissects the performance of two participants in the Wasatch Front Endurance Run, a 100-miler in Utah with a cumulative total of almost 25,000 feet of climbing and descending and a highest point above 10,000 feet. The subjects were both men, 45 and 31 years old, and both had previously completed several 100-milers. A research team led by Andrew Creer of Utah Valley University fed the subjects ā€œdoubly labeledā€ water, which contains isotopes of hydrogen and oxygen that scientists can use to figure out exactly how many calories youā€™re burning and how much water your body is using.

This isnā€™t the first time researchers have used doubly labeled water to study ultrarunners. A by Brent Ruby of the University of Montanaā€”who is also a co-author on the new paperā€”pooled data from ten runners at the Western States 100-miler and found that they burned an average of 16,130 calories while running for 26.8 hours. The twist in the new paper is that the researchers continued following the runners for seven days after the race to study how their bodies responded to the enormous physiological stress and caloric deficit they had incurred.

During the Race

Both of the Wasatch runners took 32.8 hours to finish the race. Their calorie expenditure was strikingly similar: 15,723 and 15,888 calories, even though one of them weighed 164 pounds and the other weighed 131 pounds. The bigger runner managed to take in an estimated 8,767 calories during the race, while the smaller one took in 7,429. In both cases, that means they managed to replace only about half the calories they burned, leaving an energy deficit of about 8,000 calories.

Replacing half your calories is fairly typical for ultrarunners. These runners were getting between 40 and 50 grams per hour of carbohydrate, which is lower than sports nutrition recommendations of up to 90 grams per hourā€”and much lower than the reported fueling rates of 120 grams per hour and beyond that some elite cyclists and ultrarunners have been experimenting with in recent years. But itā€™s consistent with the upper limits of what most non-pros can tolerate unless theyā€™ve been deliberately training their digestive system to handle more.

The doubly labeled water method also gives an estimate of ā€œwater turnover,ā€ which reflects how much water has been replaced in your body. During the race, the estimated turnover for the two runners was 14.6 and 15.5 liters, respectively, which is roughly 500 fluid ounces. Those numbers arenā€™t universal, since they depend on environmental conditions (the temperatures during the Wasatch race ranged from about 40 to 85 degrees Fahrenheit) and individual factors, like sweat rate. But they give a rough idea of how much you might expect to drink during a race like this.

The runners lost 3.3 and 4.8 pounds, respectively, between the start and finish of the race, which suggests only mild dehydration. Some of the weight loss is likely from the carbohydrate and fat stores they burned rather than fluid losses. Itā€™s hard to get a good estimate of exactly how much fluid they drank during the race: one runner estimated 15 liters, which makes sense; the other estimated 21 liters, which seems like an overestimate given the water turnover data. But overall it looks like they managed their hydration pretty well.

The Aftermath

There are two main things happening the day after a 100-mile race. One is that youā€™ve got a massive energy deficit to make up; the other is that youā€™ve trashed your body and need to repair it. Even marathons induce a lot of muscle damage thanks to the repeated footstrike impacts. Ultramarathons make that worse, and downhill runningā€”25,000 feet of it, in this caseā€”exacts a particularly high toll. You might also end up with some swelling, which increases fluid turnover.

Over the 24 hours following their race, the Wasatch runners burned 4,953 and 4,276 calories respectively, roughly triple their basal metabolic ratesā€”even though they were presumably moving as little as possible. Fitness magazines sometimes talk about the ā€œafterburnā€ effect following hard workouts, and itā€™s clearly a real thing if your workout lasts 33 hours. Still, their weights were back to normal within 24 hours, or in fact slightly higher than their pre-race values, which suggests that another common fitness tropeā€”compensatory eatingā€”was in full force.

Over the seven days following the race, calorie-burning drifted back down to normal levels, with seven-day averages of 3,245 calories per day for one runner and 2,721 for the other. They did no training during this period. Interestingly, water turnover during the post-race week averaged 6.0 liters per day in one runner and 3.4 liters per day in the other, illustrating the substantial the person-to-person differences that can show up in hydration habits. There was no indication that the second runner was wasting away or suffering from dehydration.

Case studies like this donā€™t necessarily tell us whatā€™s optimal. These runners were impressive but not elite: the winning time last year was just over 19 hours. Creer and his colleagues speculate that youā€™d probably want to take in more calories if youā€™re targeting elite-level performance. Still, itā€™s interesting to see detailed numbers about what it takes to cover this kind of distance. And the data on the energy demands of recovery is particularly interesting. Itā€™s reminiscent of a puzzling detail that cropped up in a study I wrote about recently on protein needs for endurance athletes: you apparently need more on rest days than you do on training days. Training is hard work; but from your bodyā€™s perspective, recovery is also hard work, so make sure youā€™re giving it enough fuel for the job.

For more Sweat Science, join me on and , sign up for the , and check out my new book .

The post Hereā€™s Exactly What It Takes to Runā€”And Then Recover Fromā€”100 Miles appeared first on ¹ś²ś³Ō¹ĻŗŚĮĻ Online.