i use one for h.s. and enduros,,, a good book to read on training might help as well,,"serious training for endurance atheletes" should be able to get it at barnes and nobles ,,,, i cant say hw much it helps yet,, but im working on it !! good luck cw;)
I use to use one on my mtn bike. I did it just for kicks... i never rode competitively, but rode about 50 to 80 miles a week. cool little rig to play around with. Mine only went up to 199 beats so it would tack out too easy!! I could ride for quite abit at 180 and practically all day at 160.
Heart rate monitors make the workouts much more efficient - a bonus for those with little time to train. I tried wearing mine while riding and found: 1/ Transmitter slid down my chest from jumps and bumps. 2/ Reciever (wristwatch) was too far away while on the crossbar pad (although this worked on my mtn bike). You could probably figure out a way to hold the transmitter on properly and read from your wrist for on the bike training.
Learn your training zones and build an aerobic base, then do intervals, 'shock' and recovery training. Presto - in shape!
I like Skid used to ride MTB with my buddies. I was 36 and the guys I rode with where early 20's so they would whip my butt. I bought an HRM and started serious training with intervals, rest days, 100 percent days and it made a world of a difference. In the MTB races I have never lost to the younger guys I rode with and took a bronze medal in the Ohio State Championship and I owe it all to the HRM. Get a good book and go to it. It will tell you when you're rested and when you're over doing it. You can tell when you're going to get a cold or some other sickness before you get it. It also motives me. Get one that will record your maximum as well as when you're in your proper time zones so you can look at it later and not when you're bouncing down the trail.