Maintaining adequate muscle mass and strength is one of the most effective ways to increase longevity. In particular, muscle strength correlates with reduced mortality from all causes in humans. Unfortunately, muscle mass and strength tend to decline with age. We’ve discussed this decline in the past, as well as how to prevent or at least limit it, but why exactly does muscle strength deteriorate?
First, let’s take a look at some of the data on muscle loss with age. This table from Peter Attia’s article on the subject shows the general percentage of muscle loss per decade after our 30s.
As people age, they lose muscle mass and muscle strength at different rates. Muscle strength typically declines faster than muscle mass.
You would be correct in suspecting that muscle mass isn’t the only factor determining muscle strength. To understand what other factors are at play, we first need a brief overview of how muscle contraction works.
How hard the muscle contracts is controlled by how rapidly the motor neurons fire, and by how many neuromuscular junctions are active at a time. From this, we can see that the quantity and quality of the muscle isn’t the only thing that matters for muscle strength: the health of the nervous system is also important.
Unfortunately, there’s currently not a lot we can do about reduced muscle quality in ageing. However, we do have more control over nervous innervation, the less well recognised player in muscle strength. This is because contracting muscles release signals which promote the growth of nerve fibres and improve transmission at the neuromuscular junction. This increases muscle strength and helps to offset the negative changes that occur during ageing. Endurance and power training appear to be particularly effective for achieving this effect.
Why do we lose muscle strength with age? https://peterattiamd.com/why-do-we-lose-muscle-strength-with-age/