The Fat Burning Zone!
When it comes to losing weight, people often want know the best way to shed excess weight. It has been shown that exercising at 60% of your maximum heart rate will bring your body into a “fat burning zone”, which is optimal for losing those pounds.
Generally, exercising at lower intensities, such as brisk walking or light jogging, doesn’t require as much effort by our muscles as other forms of exercise. This means the amount of energy needed by the body is lower, so energy supply predominantly comes from fats.
As exercise intensity increases, fat can’t be metabolized fast enough to meet the increased energy demand from your muscles. The body will shift to burning carbohydrates, because these can be metabolized faster.
What this means is that there is an exercise intensity where fat is the predominant energy source.
At the lower end of this spectrum is our resting state. Here, the number of calories our body needs to function is considerably low, so the body primarily metabolizes fat to use for energy. This means the potential “zone” for metabolizing fat is somewhere between resting state and the level of exercise intensity where we shift to burning carbohydrates.
By measuring how much air a person expels during an exercise test which gets progressively harder, physiologists have been able to calculate the relative contributions of fat and carbohydrates to meet the exercise demand at different intensities. The highest amount of fat burned is called the “maximal fat oxidation rate” (or MFO), and the intensity this occurs at is known as “FATmax”.
Studies have shown that as exercise intensity increases from around 40-70% of a person’s VO2 max, there is an increase in the rate of carbohydrates and fats being metabolized. The rate of fat being burned starts to decline at higher intensities as the body requires energy more rapidly.
The “fat burning zone” has been shown to occur anywhere between about 50-72% of a person’s VO2 max. However, the ability to burn fat is also based on genetics, with studies showing that this fat burning zone is likely to be lower in overweight or obese people, around 24-46%of their VO2 max, and much higher in trained athletes.
Everyone has their own individual ‘sweet spot’ which can be used to optimize their exercise to lose weight.
Regular physical activity around this ‘sweet spot’, which typically occurs at a low to moderate effort, for example 30-60% of your maximal effort, will likely improve your body’s efficiency in using fat for energy. This is the “fat-burning zone” for you!
Physiology in Action
HEK-TR ROAM Metabolic Physiology Lab Kit with Wireless EMG/ECG