Originally Posted by Bramble

I spoke with an exercise physiologist once about interval training. His main point was actually more about heart health. That the sudden drop off in intensity when you go from a high intensity period to a rest period exercised the heart muscles more then exercising at a constant heart rate. And that you'd see more improvement faster doing intervals. Also was supposed to help with the body’s physiological reactions to stress and surprise.

On the other hand he also told me that all that was for the gym, when I was on my bike I should just ride and not worry too much about keeping my heart rate in certain zones when I'm on my bike. I just wear my heart rate monitor when I ride just to keep track of the average heart rate, and to see how high it gets on the hills.