Cardio equipment at the gym often displays a “fat burning zone,” which involves a relatively leisurely 50 to 60 percent of your maximum heart rate. But does staying in this lower-intensity range really burn more fat than higher-intensity exercise?
VIDEO TRANSCRIPT
The Claim: Lower-intensity exercise burns more fat.
If you use cardio equipment at the gym, you’ve likely encountered the “fat burning zone.” That’s the range you’re supposed to stay in — 50 to 60 percent of your maximum heart rate — for optimal weight loss. Go above the range, and you’ll have diminishing returns. In other words, exert less effort, lose more fat. If you think that sounds too good to be true, you’re right.
When you exercise, your muscles can use stored fat or carbohydrate as fuel.
How much of each depends on how hard you exercise.
If you work out at a lower intensity… walking on the treadmill, for example… most of the calories you burn will come from fat.
Step it up to a run, and the percentage of calories from fat goes down while, the percentage from carbohydrate goes up.
Sounds like walking is better, right? Well, the catch is that running burns more calories overall. Explaining this involves a little math. Let’s assume that you walk for 30 minutes and burn 125 calories. 80 percent … or 100 of those calories… might come from fat. But go for a 30-minute run, and you can burn 300 calories. Ok, stay with me here. Even though a lower percentage – say, 50 percent – would come from fat, that still adds up to 150 fat calories, which is more than the 100 fat calories you’d burn through walking.
Of course, lower-intensity exercise like walking can be good for your health, so if that’s your thing, by all means continue.
But to burn as many calories as you would from a half-hour of a higher-intensity activity, you might need to walk an hour or longer – and the brisker the pace, the better.
In short, the longer and more vigorously you work out, the more calories and fat you burn. It’s that simple – and unfortunately that hard!
For the truth about more fitness-related claims, check out my book, Fitter Faster. You’ll also learn how to slash your workout time and get even better results.
Helping you be a healthy skeptic, I’m Robert Davis.