How exercise stops the ageing process
Interval training, in particular rejuvenates cells, a new study finds.
Exercise, and in particular high-intensity interval training in aerobic exercises such as biking and walking, can effectively stop ageing at a cellular level, a new study suggests.
Research, published in Cell Metabolism, showed that the physical activity caused cells to make more proteins for their energy-producing mitochondria and ribosomes, which are responsible for producing our cells' protein building blocks..
"Based on everything we know, there's no substitute for these exercise programs when it comes to delaying the ageing process," said study senior author Sreekumaran Nair, a medical doctor and diabetes researcher at the Mayo Clinic in Rochester, Minnesota. "These things we are seeing cannot be done by any medicine."
The study involved 36 men and 36 women from two age groups – "young" volunteers aged 18-30 years and an older group of 65-80 years. It set these two groups to work in into three different exercise programs – high-intensity interval biking; strength training with weights; and a combination of strength training and interval training.
The researchers took biopsies from the volunteers' thigh muscles, compared the molecular makeup of their muscle cells to samples from sedentary volunteers and assessed the volunteers' amount of lean muscle mass and insulin sensitivity.
While strength training built muscle mass, high-intensity interval training yielded the biggest benefits at the cellular level.
The younger volunteers in the interval training group saw a 49% increase in mitochondrial capacity, and the older volunteers saw a 69% increase.
Interval training also improved volunteers' insulin sensitivity, which indicates a lower likelihood of developing diabetes.
Ageing is marked by the steady decrease of the energy-generating capacity of our cells' mitochondria. There is evidence that all exercise encourages cells to make more RNA copies of genes coding for mitochondrial proteins and proteins responsible for muscle growth. Exercise also appears to boost the ribosomes' ability to build mitochondrial proteins.
Muscle cells divide rarely and, like brain and heart cells, wear out and aren't easily replaced. Functions in all three of those tissues are known to decline with age.
"Unlike liver, muscle is not readily regrown. The cells can accumulate a lot of damage," Nair said. He suggested that, if exercise restores or prevents deterioration in muscle cells, there's a good chance it does so in other tissues, too.