On most of the cardiovascular machines in the gym, you probably see a fat-burning zone button. So, the question here is, what is this fat-burning zone button? Should we press this button whenever we perform cardio on these machines if our goal is to lose body fat? Is there anything true about this zone, or is it just a marketing gimmick adopted by the exercise equipment industry?
These gym equipment manufacturing companies claim that you will burn more fat if you perform cardio in this zone. The thought is that working out in this zone, which is about 60% of the maximum heart rate, will burn more fat than working out at a higher intensity because these lower-intensity exercises use fats as their primary fuel source, not carbohydrates. Although this might be a logical concept, it is an inexact science.
As our exercises intensity increases, carbohydrate becomes the primary source of energy, not fats. To put it into simple words, when our body is at rest, more than 85% of the calories burned come from fat. When we move from rest to slow jogging, this figure also shifts to 70%. When we transition into moderate-intensity running, this ratio becomes 50% fat and 50% carbohydrate. And on the high-intensity run, this ratio tilts in favor of carbohydrates. Based on this concept, people think it will help them lose more fat if they do lower intensity exercises. But here, we are completely ignoring the basic idea that losing or gaining weight is a matter of calories in and calories out.
Let’s take an example- One person who performs low-intensity jogging on a treadmill for 20 minutes at a 3.0 mph speed may result in an RQ(Respiratory quotient- the amount of carbon dioxide expired divided by the amount of oxygen consumed) of 0.80. An RQ of 0.80 means that 66% of energy coming from fat and 34% from carbohydrates. Suppose if he burns 5 calories per minute, the total calories he will burn after 20 minutes of jogging are 100 calories out of which 66 comes from fat and 34 comes from carbohydrate; if the same person increases the intensity to 6 mph for the same 20 minutes, this increase in intensity requires more carbohydrates as fuel which might result in an RQ of 0.86. It means that 54 % of the energy comes from carbohydrates and 46% of energy from fats. However, running at this pace burning at about 10 calories per minute. The total number of calories he is burning by spending the same 20 minutes is approximately 200 calories, out of which 108 calories are from carbohydrates, and 92 calories are from fats, respectively.
So, the conclusion is that increasing intensity raised the total calorie expenditure from fat and carbohydrates. If we want to lose weight, we must focus on total calorie expenditure, not just calories from fats. Anyone saying that low-intensity exercises put you in the fat-burning zone is completely lying.
On most of the cardiovascular machines in the gym, you probably see a fat-burning zone button. So, the question here is, what is this fat-burning zone button? Should we press this button whenever we perform cardio on these machines if our goal is to lose body fat? Is there anything true about this zone, or is it just a marketing gimmick adopted by the exercise equipment industry?
My advice is to always focus on high-intensity exercises rather than long-duration low-intensity cardio exercises if you want to lose weight
Jobanpreet Singh
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