The best thing I could possibly do for my health after I retired was to pursue Camp Hosting positions. I eventually landed 2 location that "can" keep me busy year round. If it were not for Doctor visits, tax stuff to do, pet vet visits, and banking, we'd probably never go back "home" where my son is living in our house.
As stated, the best thing has been Camp Hosting. One location is at a state historic site in Louisiana (Audubon State Historic Site). There is no campground there, but a site for full hookup RV's. The position is "tour guide". But I've added historic blacksmithing demonstrations, historic carpentry demonstrations, historic talks and discussions on 1800's slave life on the plantation. In addition, I work my a$$ off fixing, repairing, hauling, lifting, sweeping, climbing, adjusting, painting, dragging, pulling, pushing, carrying, using my brain, my past talents with both information technology and carpentry, and my "gift of gab" to keep the old body moving, active and active. My brain is challenged every day as I'm constantly learning more and more about history, life of the slaves, Louisiana history, the Civil War, plantation life and the economics of the United States over the last 200 years. It's enough to keep even a "person of young age" physically and mentally challenged beyond their own expectations. It keep me feeling good. My wife and I are here about 8 months of the year.
The second Camp Host position is at the Pilot Mountain State Park in North Carolina, where I do more conventional "Camp Host" duties. But, because this campground is located on the side of a mountain, it creates a LOT, and I mean a LOT of exercise simply to move from point A to point B, anywhere on the property. Plus, there are a few thousand acres of property and trails to hike, explore, discover, and enjoy. The "work" requires cleaning up the campsites when people leave. That means cleaning out fire pits and keep the tent pads clear of leaves and falling sticks from the trees, and keeping the ground picked up from trash. Between climbing up and down to reach each campsite, AND the bending, stooping, reaching, carrying, and hauling to clean the ashes out of the fire pits, it requires a lot of energy, leg strength, and muscle. Add to that using a leaf blower to blow off leaves and rocks from the asphalt road and asphalt parking spaces at each tent site, weeding, edging, and cleaning off sand and rocks from the road and campsite parking spots after a heavy rain, it demands a lot of physical effort.
And yes, this does result in some aches and pains and muscle strains. Right now I'm experiencing a stiff neck (left side, back of the neck from below the back of the ear to my shoulder) because yesterday I got too aggressive and too long with a leaf blower.
It seems, every time I physically do something, that night I experience a new muscle pain, a new muscle that got a work out that has not been driven that hard in a while. Muscle aches last for about 2 days and then go away.
Over the last 5 years, I honestly believe my body is stronger and has more stamina than when I was 33. Now granted, I cannot lift 100 pounds any more, and I cannot "run"... only because of an artificial knee that still feels awkward when attempting to "run."
What I'm rambling about is simple: If you have no purpose any more, find yourself sitting in a chair like a couch potato, have no motivation to do anything, finding your body is getting stiffer and stiffer, pains come more and more, and the slightest movement seems to be an inconvenience, then you REALLY need to do something that will put your body to work. Volunteering as a Camp Host does not involve everything I do. But it does require getting up from the easy chair ever now and then and moving the body. I choose to do extra work and activities for the sole purpose of forcing my body to keep active. And keeping it active is keeping it from feeling like I'm actually now 71 years old.
As I've recommended many, many times, volunteer. Get out of that chair and do something for someone else. This benefits them, but it will benefit YOU much more.