Fat Burning Zone

When it comes to losing fat, most of us dread the high intensity exercises and exertion that comes with it. But 'fat burning zone' technique claims that the body burns higher amount of fat during long, slow and low intensity training when compared to high intensity training. According to this theory, though lower intensity levels consume fewer calories, larger percentage of it comes from fat. But what is the logic behind this idea?

As we all know, body derives its energy primarily from fat, carbohydrates and proteins. When we are carrying out low intensity exercise, 60% of energy is drawn from the fat stored in our bodies; 35 % comes from carbohydrates and the remaining 5 % from proteins.

But when the body shifts from low intensity to high intensity workouts, it tends to use up more carbohydrates and less fat. The reason being, the quick and high intensity movements require high levels of energy at a faster pace whereas fat is slow in releasing the energy.

As a result, body starts using carbohydrates as its fuel to cope up with the quick movements. Hence this technique believes that fat burns more easily at lower intensity workouts as body has enough time to draw from the fat rather than using up the carbohydrates. So the 'fat burning zone' represents the optimum level of exercise intensity at which the fat oxidation is maximized.

How do we calculate the fat burning zone?

To ascertain the fat burning zone, find the maximum heart rate that falls under fat burning zone or at which the body utilizes fat as its main source of fuel. Then choose the exercise intensity that maintains the calculated heart rate to derive optimum benefit.

Firstly, to calculate maximum heart rate, subtract your age from the numeral 220. For example, if your age is 30, the maximum heart rate is 220 minus 30, which is 190 beats per minute. This is approximately the maximum heart rate.

Now, the maximum heart rate, thus arrived, should be multiplied by 0.60 to find out the lower end of the fat burning zone and by 0.70 to arrive at the higher end. In this case lower end equals to 114 beats per minute (190 multiplied by 0.60) and higher end equals to 133 beats per minute (190 multiplied by 0.70).

According to the calculations made above, your fat burning zone, from 60% to 70% of the maximum heart rate, is 114 to 133 beats per minute. If you remain in this range while exercising you will be burning fat rather than carbohydrates.

Fat burning zone sounds very attractive and you may instantly want to tune your workouts according to the intensity that falls within the fat burning range. But, as we discuss the effectiveness of this concept, look at arguments that claim that the fat burning zone is nothing but a myth.

Fat Burning Zone Myth

According to this theory, though fat burning zone uses fat as its primary source of fuel, it is the overall consumption of calories that matters in weight loss. During lower intensity workouts, though higher percentage of fat is used, the calories burnt in absolute terms will be lower compared to the calories burnt with higher intensity exercises. This is merely because in the given time, higher intensity cardio exercises burn double the calories when compared to low and steady exercises.

For example, a person works out for one hour adhering to the target heart rate set by the fat burning zone, and burns 200 calories. In such case 60% of 200 calories are coming from fat which equals to 120 fat calories. Suppose that person shifts to higher intensity exercises and burns 400 calories per hour, only 35% of it comes from fat.

Yet, if you calculate, he would burn 150 fat calories (35% of 400 = 150 calories) which is higher than the amount he burnt while on lower intensity exercises. So this proves the point that weight loss is higher when the heart rate crosses the fat burning zone.

There is one more interesting aspect to high intensity exercises. Working at high intensity revs up your metabolism which, in fact, continues to remain active even after the exercise session is over thus allowing you to burn calories throughout the day.

Does this mean that, fat burning zone does not exist at all? Should we go beyond the maximum heart rate of fat burning zone and start working out in the fitness zone? In reality, there is no single way to lose weight; a balanced approach is the key to achieving weight loss goals. Combining both low and high intensity workouts, also known as interval training, helps achieve effective results.