My Dad used to say "Getting old is not for the faint of heart". He had various health issues, and made it to 91. He was taking an awful lot of pills toward the end and using a walker the last few years. I guess I'm pretty lucky so far. No significant health issues or injuries, other than a fingertip that got shot off with a SBR. I take 1 pill for chloresterol and one for acid reflux. 70, 5'10 (probably 5'9" now), about 175, 34" pants, which includes an extra inch for the appendix carry CCW except when sleeping. Wife says I act 14. Retired from IT world in 2015, busier than ever, can't imagine how I had time for a JOB before. My Dad said the same thing, as have numerous other retired people I've talked to.
I'm more calm, patient, and mature than in my younger days, but otherwise I feel like the same person. I do have to remind myself to take things careful and easy and not get hurt. I have a wonderful wife who takes great care of me and makes sure I eat very well.
The most age-related physical issue I have is shooting iron sights sure isn't what it used to be, and if I squat down, getting back up is a surprising amount of effort. And I get tired more easily. If I'm logging, a few hours is about it and I'm worn out. If I'm doing heavy brush cutting with a body-mount brush saw, one tank (about 1-1.5 hour) is enough for one day for me now. Muscles, like pulling on a big wrench, aren't what they were, but cheater pipes are always available for more torque. I know I should do regular exercise, but I'm always too busy. The way I ride a dirt bike or snowmobile is a pretty good workout. My muscles are also more susceptible to aching if I overwork.
My sleep patterns have gotten worse - I always was a night owl. Gradually, over the last couple years, I've devolved from going to bed at 1, then 2, then 3, then 4, then 5, into being up most of the night, often until dawn, then sleep to noon or so, maybe as late as 1 or 2 in the afternoon, generally a nap right after supper for 15 minutes to 2 hours, usually about 30-40 minuets, depending on how tired I am, then I'm re-energized until dawn again. Occasionally, a few times a month, if it's a beautiful day and it's much past dawn and I'm still up, I say screw it and keep going into the next day, although I pay for it in the afternoon and have to take a long nap of several hours. Basically, I just follow what my body is telling me and sleep when it tells me and up the rest of the time.
I cut and split all our firewood from our property, and all our (northern NH) heat comes from that. I deliberately move a bit slower and try to pace myself when shoveling snow and doing other heavy work. I still climb up on the 2-1/2 story roof after every snowstorm to clean the snow off the solar panels. I suppose eventually I won't be able to.