Scientists have just figured out why there is a natural loss of muscle in the legs in elderly people, and they have connected it to a loss of nerves, a huge discovery that has tremendous medical implications. The study, published in the Journal of Physiology, is based on tests on 168 men, which found that nerves in the legs declined by 30 percent by the age of 75.

It has long been understood that leg muscles become smaller and weaker as we age, which can result in problems with basic movement for the elderly. But scientists had not really understood why that is, and this study suggests that the nerves may be at the root of this muscle loss.

The study found that older people who had remained in shape had a better chance of nerves re-connecting. These nerves need to be able to send a good signal from the nervous system to tell them to contract, which in turn affects the fitness of the muscle itself.

“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,” said Professor Jamie McPhee, the senior author on the research, in a statement. “Right now in Europe there are at least 10 million older people with low muscle mass, which is a medical condition known as sarcopenia. They are at higher risk of social isolation, falling, bone fracture, disability and hospital admission. Weakness makes them particularly vulnerable to falls in bad weather, as we’ve had in recent weeks. Our research helps to explain why muscles decline with advancing age and this new knowledge will help in the search for effective countermeasures.”