I just think it depends on an individual's state of health, I know my father went from active to non active when in later life he had a whole gamut of health conditions that precluded him from following previous routines, it's what life deals you as to health and fitness. I wish I had more stamina, I think that's something I realised quire a few years ago, goes somewhat hand in hand with an under active thyroid and it's amazing how different I feel on some days as to energy levels without any noticeable related triggers that come to mind. I have to push myself a bit in that respect on sluggish days. I'm sure the old adage of "if you don't use it you'll lose it" is very true. I have to give it to my husband, golf does pay off in later years, it's certainly kept him very fit and he frets when he's not getting enough because of adverse weather, of what, for him, and many others is an enjoyable form of exercise.