Weight Management

Fat Loss: High Intensity or Low Intensity Physical Activity?

Prof Hazza Al Hazza/ KSA 08 February, 2016

No Image

أنقر هنا لقراءة باللغة ألعربية

For those who desire to reduce weight, one may consider whether it is better to practice physical activity at low or high-intensity. Which is better for burning more body fat? It is certainly at the low physical activity, the muscles are working to burn a higher percentage of fat as fuel compared to high intensity. To explain this, we can say it is true when physical activity intensity is low, the proportion of the use of fat as fuel will be higher (70%, for example), but the calories consumed from fat burning energy during the moderate intensity may be less, as well as the amount of fat used is possible to be less than if it were at a high-intensity physical activity. But how can this be explained?

First, it is well known that the body uses both fat stored in the body as well as carbohydrates as an energy source. When the intensity of the activity increased the proportion of carbohydrates fuel used lowered. It is also known that the energy produced from the burning of one gram of fat is more than twice the amount of energy produced from the burning of one gram of carbohydrates (produced 9.3 kilocalories when burning one gram of fat versus 4.1 kcal when burning one gram of carbohydrates).

However, the fat also consumed more than double amount of oxygen consumed in case of burning one gram of carbohydrates (per gram fat consumption requires two liters of oxygen compared to 0.8 liters of oxygen when burning one gram of carbohydrates). So At high intensity physical activity, the body prefers to use carbohydrates than using fat as fuel due to the lack of sufficient oxygen in the high Intensity activity. So burning carbohydrates in this case gives the body a higher power level for every liter consumed oxygen compared to fat. Therefore burning carbohydrates is more economical in use than oxygen (giving carbohydrates: 4.1 ÷ 0.8 liter oxygen = 5.06 kcal per liter oxygen, and give the fat: 9.3 ÷ 2 liters of oxygen = 4.65 kcal per liter of oxygen consumed).

It's true during the low-intensity the proportion of fat burning up is about 70% as compared with the proportion of fat burning equivalent to 60% in case of relatively high intensity. If we assume that a person weighing 75 kg will walk quickly equivalent to 4.8 kilometers per hour (low intensity), it is expected that this person will consume within one hour of walking at that speed about 330 kilocalories, and thus the energy resulting from the burning of fat are in this case equivalent to 231 kilocalories (330 × 70%). Let us assume that the same person will walk then with a speed of 6.4 kilometers per hour (intensity is relatively high), he is expected to consume in an hour of brisk walking at that speed an energy equivalent to about 440 kilocalories, and thus the energy generated from the burning of fat in this case equivalent to 264 kilocalories (440 × 60%). So it found that the amount of energy resulting from the burning of fat in case of the high speed is greater than those resulting from the burning of fat in case of low-speed (264 versus 231 kcal) Although the fat burning rate was higher in the low-speed (70%) compared to high speed (60%), and this means that the amount of fat that have been burned during high intensity are more compared to low speed (14.3% greater than in case of low-intensity exercise), in addition to bigger total energy consumption during high intensity exercise.

The advantage of the relatively high intensity exercise (walking at higher speeds, for example), it increases cardiorespiratory fitness level of the person, which makes enables him to perform his daily routines activities more efficiently.



rate this article



Total Comments (0)

Read the Latest Issue of Namat Magazine


Latest Photo

Latest Video