Although scientists and philosophers have speculated that time is not real (though they have never missed lunchtime on that basis), it certainly seems to be real enough as an opponent.
When I hit 40 and won my first Master’s award (Master=old), I started looking into the impact of aging on running. I had, of course, learned about aging back when I took anatomy and physiology, but this was a bit more real. While I will spare you the details, the gist of it is that once we humans hit our mid to late twenties, we start a slow spiral downwards (or rapid, depending on how one handles it). While everyone notices this, competitive runners tend to notice it more. This is not because we are somehow more realistic or more perceptive. Rather, it is the fact that we get to see the aging play out it cold, objective numbers as our times get slower and slower. There is also the subjective factor: runs seem to hurt more, one’s stride feels less snappy, and recovery seems to take longer. Or maybe gravity is just increasing in a selective manner-that is, under me.
Fortunately, there is some compensation for these harsh facts: running and exercise in general can be used to fight time. Running is especially effective at literally keeping the cells younger (no magic, just biology) which is why runners often look younger than they are (or, more aptly, other folks look older than they should). Exercise is also critical to resisting two major problems of aging: muscle and bone loss. Like an eroding sandbar, time eats away at the very makeup of our body. Fortunately, exercise that builds muscle and bone can slow down this loss, thus enabling the body to handle aging better. Exercise can also help with balance. Since falls tend to be a major threat to the elderly, building up your fall avoidance and resistance is a smart thing.
Exercise alone, as they say about losing weight, is not enough: diet is also important. When I was young, it mattered less what I ate (or so I thought). Being older, I have less margin of junk (so to speak), and I have had to change my diet to be significantly more healthy. What is actually pretty cool is that what I eat now is not only better for me, but it actually tastes better than much of what I used to eat. It does help that I am not a poor graduate student: eating well is not a luxury, but it is not as cheap as ramen and generic rice puff cereal.
My main goal is not to live really long (although I am fine with that) but to have a good life as long as possible. That seems to be something almost any of us can do, with a little planning and a lot of sweat.
In the end, however, time kills us all. But all races must end and the glory is in the running.