This is probably the number one exercise myth that despite it’s lack of evidence never seems to be truly debunked.
You still even see on the cardio gym equipment to this day heart rate graphs of the optimal zone to burn fat, implying that if you stick in this low zone you’ll lose more weight.
I am hoping that the evidence I am about to show you will debunk this myth once and for all.
Last year I had posted on the benefits of high intensity exercise on losing belly fat showing that it is a great way to tone the midriff. This blog explained the results of one particular study published relatively recently, so it surprised me to find this evidence was hiding in a review by Ross & Janssen published way back in 2001. Here is a very similar graph that was published in this paper, which the authors of it concluded that to lose more fat you simply need to burn more calories.
Fairly straight forward right?
However, I’ve taken the liberty of highlighting the results of particularly studies that used low-to-moderate intensity exercise (as represented by the blue dots) compared to the high intensity exercise interventions (highlighted in orange).
Now we can compare how far away these studies are away, on average, from the line of best fit. While the high intensity studies tend to be 1.35 kg above the line for any given energy expenditure, the low intensity studies fall below the line by 0.35 kg. Therefore for a given amount of calories burnt in these interventions the high intensity studies performed 1.7 kg better!
Certainly this debunks the myth that low intensity exercise is better for fat loss but here’s the great news! When you are working at high intensities you’ll burn your calories twice as fast as if you work at low intensities.
So not only will you lose over 60% more weight on a high intensity program, you’ll get there in half the time!
Now one thing I should highlight is while these studies did not have any dietary intervention, some of these studies were getting people to exercise at greater than 300 minutes a week to get fat losses of 5-6kg over three months. If you can’t devote that amount of time, or would like to lose more weight, then it’s best to combine both dietary changes and exercise.
You also may feel that high intensity exercise, which involves getting a sweat up, is outside of the realm of your capacity, or you may have other health conditions that need to be taken into consideration. This is where you may find that an Exercise Physiologist can help you with this journey, ensuring that you get the best possible program for your needs.