Friday, March 14, 2014

Crunching the numbers on Jim Saret's 4-minute-workout

For the people interested in the technical and scientific debunking of Jim Saret's Burn- 600-Calories-in 4-Minutes workout:

The unit for measuring exercise intensity is METs or Metabolic Equivalents.
MET is equivalent to burning 1 kcal/ kilogram of body weight/ hour or using up 3.5 ml of Oxygen/ kilogram of body weight/ minute (Vo2 Max). This is how much you burn when you are just resting.

The highest MET recorded is 16.3 METS . This is like finishing a 1 mile run in 6 minutes.
That’s equivalent to 0.27 kcal/ kilogram of body weight/ minute of exercise.
So with this high intensity, a 70 kilogram person will burn 18.9 kcal per minute
At 16.3 METS and 0.27 kcal/ kg/ min
600 kcal=0.27kcal/kg/min x Body weight ? X 4 minutes
To burn 600 kcal in 4 minutes with the highest recorded METS or intensity, you have to weigh 555.5 kilograms
If you weigh 70 kg and you exercise at at intensity of 16.3 METS for 1 hour
16.3 METS= 16.3 kcal x (70 kg) / 60 minutes= 19 kcal/ minutes or 76 KCAL IN 4 MINUTES is what you will possibly burn
Any exercise more than 0.22 kcal/ kg Body weight/ minute is classified as extremely high intensity exercise with an Oxygen consumption of 3 Liters minute.
If you burn 600 kcal in 4minutes, you have a Metabolic Equivalent of 128, for a 70 kg person.
Again, the highest recorded in our references is 16.3 MET.
If there is an exercise that can cause you to burn 600 kcal per minute then that is a very, very high intensity exercise with a metabolic demand which goes beyond the body’s physiologic limit.

Reference: Exercise Physiology for Health Fitness and Performance  (Plowman & Smith, 2011)
Special hat tip to Professor Maghanoy, from UP Diliman Sports Science