Carefully watching your heart rate is indeed an excellent way to monitor your training level. I prefer a simpler method聴if I feel as if I’m going to throw up, I back off a little.
Polar A3
I kid you. (Sort of.) There are lots of excellent heart-rate monitors out there, one of which is Polar’s A3 ($80; www.polarusa.com). This unit allows you to set target= zones and receive a beep warning when you’re in or out of them, in addition to basic time/heart functions. Bike Nashbar sells a monitor with basically the same features for $50 (www.nashbar.com), one seriously good deal. Or, you can spend a ton of money and get something like Polar’s S520 ($280), which provides a link to your PC so you can set up a personal training log. As if…
All of the aforementioned models require a chest strap, which contains the sending unit. You might prefer a monitor that takes a reading off your wrist, such as a Sun Heartmeter ($89; www.rei.com), offering basic heart-monitoring functions in a wristwatch-style unit. I haven’t used such a unit, so I can’t say how well it will work.
Otherwise, you know the rules: Know your VO2 max limits (maximum heart rate), and see a doc for a checkup if you’re over 40 and have any questions at all about what you’re capable of doing. And if you’re about to toss your lunch, back off…