Aging, combined with a sedentary lifestyle are major risk factors for obesity, diabetes, osteoporosis, heart diseases and reduced brain function. Muscle mass and function (including strength) decline with age as well. In laboratory animals, researchers found that endurance-type exercise increased the number of stem cells found in muscles; stem cell numbers typically decline with age.
Stem cells are known for their ability to produce new cells of varying types throughout the body. Each cell in our body can only divide so many times during our lifetime before they die; however stem cells can give rise to ‘new’ cells that haven’t aged yet. This is why there is so much intense research going on in this field – stem cells can potentially repair and replaced the worn out parts of our bodies.
In one study, older animals had a 33% to 47% increase in stem cells after exercising in increments over a 13-week period, whereas younger animals showed a 20% to 35% increase in stem cell numbers.
So what does this mean? It means that exercise can help keep your muscles young, quite literally. And it appears that exercise becomes more important in supporting youth as we age.
Shefer G, Rauner G, Yablonka-Reuveni Z, Benayahu D. “Reduced Satellite Cell Numbers and Myogenic Capacity in Aging Can Be Alleviated by Endurance Exercise.” PLoS ONE 5(10): e13307; doi:10.1371/journal.pone.0013307.