The scientists from the University of Utah have proved once more the positive impact of exercises on the body. In addition to its effects on heart, weight, and overall health, moderate exercising helps to restore muscle mass which usually diminishes as we age. The results of the study were given light in the journal Free Radical Biology and Medicine.
Our body starts experiencing age-related loss of skeletal muscle mass, or sarcopenia, mostly around age 30. To slow down this process, our bodies produce antioxidants which help regenerate stem cells that turn into muscle cells and thus maintain muscle mass.
As we age, our bodies produce fewer antioxidants, and researchers have not found all the reasons for that yet. When the amount of antioxidants in the body diminishes, we experience oxidative stress – condition in which free radicals that are rogue electrons can travel throughout the body and trigger chemical reactions resulting in the damage to cells and proteins. During the oxidative stress, stem cells cannot regenerate muscle cells as quickly as they get lost which results in muscle loss.
In a study, the researchers compared the reaction of two groups of old mice (equivalent of elderly people) to two week exercise stress on treadmills, in other words, oxidative stress. One group of mice was lacking Nrf2 proteins, while the other was able to produce it. The group unable to produce Nrf2 showed poor muscle regeneration.
Nrf2 is a protein that regulates antioxidants production by turning on and off the relevant genes. Regeneration of adult skeletal muscle mass after damage and/or stress requires activation of stem cells. In a group unable to produce Nrf2, stem cell protein expression and muscle regenerative capacity were very poor.
With that important role of Nfr2 in mice, the researchers plan to conduct the similar study in humans. However, they can conclude even now that moderate exercising can prevent muscle mass loss while too much of endurance training may have the opposite effect.