Just a quick comment about this article, since I’ve been reading about it – age-related muscle loss.
Muscle Loss In Old Age Linked To Fewer Nerve Signals, BBC, 12 March 2018

The article says that people lose muscle as they age. Check. And it says that people lose nerves in their legs as they age. Interesting. But it does not say that being fit or exercising prevents that nerve loss, only that it can help, after-the-fact:

“Surviving nerves can send out new branches to rescue muscles.”

So, we’re back to losing muscle (and nerves) as we age and not fully understanding why.

As people get older, their leg muscles become smaller and weaker, leading to problems with everyday movements such as walking up stairs or getting out of a chair.

It is something that affects everyone eventually, but why it happens is not fully understood.

Although it is not known why connections between muscles and nerves break down with age, finding out more about muscle loss could help scientists find ways of reversing the condition in the future.

Exercise is just one part of the equation. As I’ve discovered, exercise cannot by itself stem muscle loss. There are other variables:

1. People have to consume enough calories, and enough nutrients (this becomes more difficult with age).
2. Contrary to popular belief, studies show that eating more protein doesn’t seem to help.
3. There has to be the right mix of hormones … growth, sex.
4. A state of low-level metabolic acidosis (the result of a diet that is net acid-forming) contributes to muscle and bone loss.

This BBC article raises the issue of nerves. Sarcopenia, it’s complex.