[Dan in Pasadena]

A question for you workout nuts.

I am resuming regular use of my road bike (hit by a car 3 years ago; uninjured - mostly, but had the poop scared out of me!)

I have always heard that a rule of thumb for max heart rate is 220 less your age. That would make mine 168 since I am age 52.

My question is - what sustained percentage range of your maximum heart rate must you stay in to maximize fat burning?
I think I remember being told it is lower than you might think...like 60% to 70%? If so that makes my range only about 100 to 120 beats per minute. That doesn't seem very high at all...is that right?

I checked Wikipedia and there are several methods for determining max heart rate but I can'tfind anything accurate that says what percentage of it to stay in, and for how long?