Interesting how this is the opposed of fitness recommendations where it’s all about mTOR activation to build muscle with protein or even pure leucine supplements. That would imply a strong inverse correlation between muscle mass and longevity, but I’m not aware of research showing this, even maybe the opposite. How do you explain this apparent paradox? Maybe the problem is mTOR over activation, not an intermittent one, kind of like insulin? In that case phases of muscle building with autophagy in between (ie intermittent fasting) could be the best of both.
I believe you're on the right track. To me, it only seems paradoxical when viewed in isolation. mTOR activation is conducive to growth, but unchecked growth is called cancer.
A person (and the processes in their body) goes through cycles on a daily and long-term basis. One is not constantly eating, exercising, and growing.
Muscle mass and strength are not the same thing, though they are highly correlated. I believe most studies on the elderly use measures like grip strength, which is a proxy for frailty.
The elderly don't have the same capacity for growth or energy. However, they can avoid wasting away by remaining active. They certainly benefit from autophagy as it clears senescent cells. Perhaps this shift is the body's way of reducing the risk of cancer.
As an aside, a curious data point is that men have shorter lifespans than women on average. There are likely several reasons for this, but I wonder if this has to do with the hormonal effect on mTOR. Perhaps our ability to grow is finite, and excessive activation of mTOR "runs out the clock" faster.
