Worthwhile watch for this person. There is much a person can do beyond 47 though one is unlikely to reach peak performance levels beyond 30s that is true in all sports. I seem to be on a similar path with diet, physical activity, never a nicotine, alcohol, or drug habit. Genetics probably has a good deal to do with aging but then as noted there are other factors involved.
My decades hi tech electronics career here in Silicon Valley has kept my mind sharp. Like Miura I am not one regularly working out. During ski season I mostly just ski. My skiing is often strenuous thus builds a strong respiration ability into the core of one's inner body. Frequently during the rest of the year that I've been at for over 4 decades as a landscape and nature photography enthusiast, I am hiking and backpacking carrying a lot of weight because of camera gear. Currently when backpacking, of which I did 6 trips this summer, that is about 45% of my body weight, way beyond usual. And again don't work out beyond that much otherwise because I don't seem to need to and can be lazy. That said some mountain athletes are far stronger, especially peakbaggers.
A couple of things his son, an aging researcher, said were that skiers have highest bone density of any sport and that those with longevity often engage in activities that build a strong lower body.