We are one step closer to eradicating muscle loss.
New research has looked at how we might prevent our muscles from becoming frail and wasting away as we age.
Scientists have known for some time that muscle loss has to do with our nervous system. We all eventually experience muscle loss if we live long enough, as the number of muscle nerves decline.
By the age of 75, people typically have 30–50 per cent fewer nerves in their legs, for example, than they do when they are younger.
However, healthy muscles can protect against muscle loss by having nerves send out new branches to connect to muscle fibres and save them.
This protective mechanism works best when a person has large, healthy muscles.
When this doesn’t work, it can result in Sarcopenia, a condition describing extensive muscle loss.
Researchers from the UK and Canada used MRIs to look in detail at muscle tissue from four groups of men, ranging from those with healthy muscles to those with sarcopenia.
The researchers also used enhanced electromyography to measure muscles’ electrical activity and thus the activity of the muscular nerves.
The results showed that the ‘extensive motor unit remodelling’ happens fairly early in the aging process.
This might suggest that exercise in middle-age and early old age is important in maintaining muscle mass and avoiding muscle loss.
Furthermore, the researchers concluded that what distinguishes people with extensive muscle loss from those without it is ‘a failure to expand the motor unit size’. That is, those with small or unhealthy muscles.
This suggests that exercising to increase the size of your muscles may protect against muscle loss.
Where to from here?
Further research will look at whether exercise in middle age or early old age can slow the muscles disconnecting from the nervous system. It will also try to determine what kind of exercise will best preserve the muscle tissue, strength or endurance-style training or perhaps a combination.
“Our challenge now is to find ways to increase the success of nerve branching to rescue detached muscle fibres and thereby reduce the numbers of older people in our neighbourhoods with low muscle mass and muscle weakness,” says Professor Jamie McPhee, one of the study authors.
Professor McPhee also notes that there are millions of older people with low muscle mass, which puts them at risk of falling, bone fractures, disability and social isolation.
“Our research helps to explain why muscles decline with advancing age and this new knowledge will help in the search for effective countermeasures.”
This research provides further evidence that exercising throughout your life is the best course of action. Time to head for the gym!
Piasecki, M., et al. (2018.) ‘Failure to expand the motor unit size to compensate for declining motor unit numbers distinguishes sarcopenic from non-sarcopenic older men.’ J Physiol. Accepted manuscript online: 11 March 2018. DOI: 10.1113/JP275520