Cardio On Empty Stomach Yes Or No

Let's take a look at the reasoning for doing cardio in the early morning on an empty stomach. Glycogen is depleted therefore more fat is burned this is the major benefit people who this method use to support their position. What they fail to realize is that anyone with weight training experience has more muscle than is needed to sustain a healthy life.

 
All of this extra muscle is detrimental to the survival of a human why? First of all the body has one purpose in life that purpose is survival. Fat is a much more efficient energy source for survival because it is not energy-costly. It does not require calories to sustain on top of this fat is slower burning as it is more calories dense. Therefore muscle will be burned before fat when in a state of starvation as fat will keep you alive longer.
 
That’s the catch just because glycogen stores are depleted that doesn’t mean the body will just go straight to fat stores for its energy how great that would be unfortunately it’s just not that simple. In the morning glycogen is substantially depleted, and in effect so is ATP. If you have read some of my other articles you would know that ATP is the only source of energy for muscle contraction.
 
Heavy productive weight training depletes glycogen and ATP with each contraction. ATP is not only the fuel for muscular contraction, it also plays a large role in protein synthesis and repair itself. After weight training ATP and glycogen are depleted heavyweight training uses the anaerobic glycolysis mechanism on ATP production and time is needed for glycogen stored to replenish. Glycogen replenishment can take up to 3 days to complete!
 
If you deplete more glycogen than is necessary you are putting your body through unnecessary stress which will inhibit your body's ability to build muscle. Less ATP means less energy for protein synthesis it’s apparent that you want to stimulate as much muscle growth as possible with the smallest amount of glycogen and ATP depletion, which means that you should train as little as possible while still achieving the desired results.
 

So How Does This Matter In This Situation?

Cardio in the morning on an empty stomach means cardio with little glycogen and thus little ATP. Remember that cardiovascular work requires muscle fibers to contract. Just because an activity is aerobic doesn’t mean it does not require muscle fiber to perform the work. The primary source of contraction during aerobic work because they have a long fatigue threshold meaning they can maintain the contraction for long periods.