...Skeletal muscle, given the fact that it occupies far more space in your body than anything else, is the primary key to physiology communication ... When you don't have enough of it or it is compromised, you're going to see problems in every other area of your life.

Most of your metabolism in your body is actually occurring in your skeletal muscle. In fact, because of this, around 85% or so of the heat you generate in your body is coming from skeletal muscle. It's also the primary place in which you dispose of and regulate blood glucose.

You don't have to necessarily be the fittest on the planet from a health and cardiovascular risk perspective, but you cannot be the lowest. The magnitude of improvement you see from going from the least fit people around to just the second least fit is almost half to three times the risk reduction.

There doesn't seem to be any reduction in the benefit by continuing to increase your VO2 max .... The higher your VO2 max goes, the more it seems to preserve all cause mortality risk.

Skeletal muscle is the workhorse. So nothing will actually get accomplished without the skeletal muscle ... Nothing is going to happen in your body, health-wise or actual again interfacing with the world, without skeletal muscle.

Research has shown that athletes are up to 25% more effective at disposing glucose into their muscle than non-athletes.

Directly from the paper again here: 'The increase in all-cause mortality is associated with reduced cardiorespiratory fitness, which was comparable to or greater than traditional clinical risk factors such as coronary artery, disease, smoking and diabetes.'

The quantity of muscle, compared to other organ systems—say your immune system, your brain, central nervous system, or even your bones—skeletal muscle is the one you have the most control over with lifestyle factors.

If you look at the research on sport performance, there are some clear associations—in fact, some of them are very highly tied—to success in sports and your VO2 max.

When we look at VO2 max and we compare that to say, smoking or cardiovascular disease, it's as strong if not a stronger predictor of how long you're going to live than any of these other metrics.

If I go from the least fit category to the most fit, my risk goes from 64 deaths per 10,000 people down to 18 deaths per 10,000 people.