Exercising Longer is More Beneficial Than Exercising Harder

Wait right there! Did he really say that? Is there more benefit to longer exercise than harder exercise? Well, like with most things, yes and no. First, the facts: 1) exercising harder will burn more calories per minute than exercising easier 2) You will fatigue faster by exercising harder 3) In terms of total calories burned, duration trumps intensity.

I've done some experimentation and found that when walking, I could vary my calorie burn by about 20% by going hard. If time is tight, picking a short, intense workout may be the best you can do; but keep my intensity lower will let me be comfortable exercising for 50% (or even 100%) longer.

If we look at the math, let's assume I walk at a 12 minute/mile pace (5 mph) and that's pretty fast. If I do a 30-minute workout and burn 120 calories/mile, I've burned 300 calories. If I pick up my pace to an 11 minute/mile (5.4 mph) pace and my calorie burn rate goes to 145 calories/mile but I only exercise for 20 minutes, then I burn only about 265 calories.

Do other factors enter the equtaion, like increased metabolic rate? Yes, and so does fatigue. You are more likely to feel fatigued after the short, intense exercise than after the longer, easier exercise. For me, that means I'm more likely to skip exercising tomorrow if I do intense exercise, so for me (and I suspect most others), slightly reducing the intensity is likely to mean a more successful exercise program.

Note that people training for competition will often live with that "tired all the time" feeling in order to compete better, but many find it to be a burden.

Also, long duration exercise (by this I mean 90 minutes or more), when repeated regularly (once or twice per week for about 3 months) will have a big impact in your body's ability to process oxygen (this means you can exercise harder with less fatigue) and is likely to lower your blood pressure.