On the contrary, I’m on my early forties and my physical condition is way better than it was twenty years ago.
It's a crap shoot. I got hit by metabolic syndrome -- extreme hypertension and type II diabetes. I exercise, I weigh less and am in better shape than I was 20 years ago, but I'm still on a cardiology professor's frequent-flyer list and gobbling meds by the double-handful. Meanwhile, my wife is a four year cancer survivor (another six months to the all-clear, we hope).
The probability of running into a life-threatening or terminal medical condition approaches unity as we age towards the upper limit of human life expectancy (around 114 years, currently). By the time you hit your forties you probably know people who had an unlucky aggressive early-onset cancer; by the time you hit your fifties you can add heart attacks and strokes to that, and less-well-known problems as well. It's all downhill from here, and unfortunately it's not the kind of ride most people enjoy.
Genetics
Twin studies have estimated that approximately 20-30% the variation in human lifespan can be related to genetics, with the rest due to individual behaviors and environmental factors which can be modified.
[Hjelmborg, J.; Skytthe, Axel; Vaupel, James W.; McGue, Matt; Koskenvuo, Markku; Kaprio, Jaakko; Pedersen, Nancy L.; Christensen, Kaare et al. (2006). "Genetic influence on human lifespan and longevity". Human Genetics 119 (3): 312–321. doi:10.1007/s00439-006-0144-y.]
It's a crap shoot. I got hit by metabolic syndrome -- extreme hypertension and type II diabetes. I exercise, I weigh less and am in better shape than I was 20 years ago, but I'm still on a cardiology professor's frequent-flyer list and gobbling meds by the double-handful. Meanwhile, my wife is a four year cancer survivor (another six months to the all-clear, we hope).
The probability of running into a life-threatening or terminal medical condition approaches unity as we age towards the upper limit of human life expectancy (around 114 years, currently). By the time you hit your forties you probably know people who had an unlucky aggressive early-onset cancer; by the time you hit your fifties you can add heart attacks and strokes to that, and less-well-known problems as well. It's all downhill from here, and unfortunately it's not the kind of ride most people enjoy.