If you’ve been near a gym recently you’ve probably seen charts on the walls or on the cardio machines themselves that show what your heart rate should be if you are working in either the ‘fat burning zone’ or the ‘aerobic training zone’. If you’re like most people trying to lose weight you think, “I’m trying to burn fat, I should stay in the ‘fat burning zone’.” Then, once you realize that the fat burning zone is less strenuous (i.e. pretty darn easy) you become a convert for life and never stray from the safety of that zone. If you’re like some, you even determine that the ‘aerobic training zone’ must be bad because you are, by definition, training yourself aerobically and are no longer in the fat burning zone.
That, however, is faulty logic. Let’s do some math shall we?
When you are working at 50-65% of your maximum heart rate (i.e. the fat burning zone) 50% of the calories you burn come from fat and you burn an average of about 100 call per hour. That’s 50 calories of fat burned per hour.
So far so good, right?
If you stay in your ‘aerobic training zone’ of 65 – 80% of your maximum heart rate only 40% of the calories you burn are fat calories. At first that sounds bad until you realize that at that exertion level you are burning 200 calories per hour. At 40%, that’s 80 calories of fat. And 100 more calories per hour.
So, if your time is precious and you have a hard enough time just getting yourself to the gym, what would you rather do – spend 30 minutes on the treadmill burning 100 calories (50 of which are fat) or 30 minutes on the treadmill burning 200 calories (of which, 80 are fat)?
I don’t know about you but I’d rather work a little harder than longer.