October 11, 2015
By Jared Jones
When your goal is to lose fat, you should focus on workouts that elicit the optimal hormone response to training. An article published in the European Journal of Applied Physiology looked at three exercise modes and their effects on increasing muscle and burning fat, including how they affect testosterone and growth hormone.
Researchers compared the effect on hormone levels of three different activities: a short sprint session, an endurance session and a weight workout. Specifically, the subjects did two 30-second all-out sprints, cycled for 30 minutes at 70 percent of maximum and performed a 30-minute weight-training workout using loads of 75 percent of one-rep maximum and taking one-minute rests. The purpose was to identify how each type of exercise acutely affected hormone response independently of workload or adaptation.
The results showed that the weight-training workout was the only one of the activities to trigger a significant increase in testosterone. The sprint session increased growth hormone, insulin and cortisol, which suggests that sprinting would be the ideal workout for someone whose goal is to lose fat. High-intensity exercise that increases insulin will facilitate muscle protein and glycogen synthesis, while the increase in growth hormone encourages more free fatty acids to be burned as energy, producing fat loss over the long term.
In contrast, the endurance session elevated cortisol and growth hormone and decreased insulin. Basically, the body conserved glycogen so it could continue to function as the subjects continued to exercise at a steady state. By being aware of the way energy is used in endurance exercise, we can understand why it is not effective for losing fat or building muscle. In fact, the central purpose of aerobic exercise is to teach the body to be efficient and to expend as little energy as possible while doing the work. Nothing about aerobic exercise is in line with the goals of fat loss or muscle building.
If you want to build a muscle, you need to apply a lot of stress to the muscle to create a high degree of muscle tension. The continual loading will cause the muscle to adapt and grow bigger over time. In addition, a high degree of tension has been linked to testosterone response, which is just what we saw in this study.
Learn your history first.