"Health" is a broader term than we sometimes take it for. I started weightlifting a year-&-a-half ago, because I felt that I was saying no to overtures from my son to go play frisbee or whatever, just because the effort to lever my fat ass out of the chair was too daunting. That got me imagining a future where I couldn't carry laundry baskets up & down stairs or take out the recycle or whatever. Shiver.
I was 50: that wasn't going to get better all by itself. I needed to actively intervene. The existence of strength standards at various levels — untrained, novice, intermediate etc — for my weight class & age class is great, gave me objective achievable milestones to shoot for. I reference ExRx, Rippetoe's site, and Lon Kilgore's site. I don't need to set any records; but getting & maintaining baseline strength, that some professional has determined is "sufficient for vigorous recreational activities," is useful. Some reasonable guidance on what constitutes "strong enough".
Judo - I'd always been curious about Judo, interested in giving it a try. When I started hitting the gym regularly, I re-noticed the club that meets in the gym weekly (actually 2x a week). I'd been away from martial arts long enough that I didn't feel any need to posture myself as anything but a beginner. "Free to be a beginner" was nice. I think we often fail to undertake rewarding challenges, because we're reluctant to be the stupid kid in the class: we're uncomfortable being the beginner. That's a trap.
In strict isolation it's possible that Judo isn't so great for my joints etc. But my wife says I'm "so happy" when I come home from class. There's a "glowing sweaty triumph" aspect, and a social aspect, and a mental challenge aspect, and a high-intensity cardio aspect. It's globally pretty great, even if there's one aspect (joints & impact) that I have to manage carefully.
You have an observation. Let others decide if it's interesting.
Piano lessons! I've been shocked at how fun and involving that is. There's a mental aspect: key signatures and scales and chords, and counting different rhythms & note values. There's a psychomotor coordination aspect for the movement of the hands & fingers. And, after a little practice, there's music! Real music. It's amazing. It's just fucking fun to create music with your own physical actions. When it's Bach or Beethoven, even the easy pieces that are within my reach are compelling, just super interesting. You want to play them again and again. And that's just the threshold! Next you get to "musicianship" in every piece: phrasing, dynamics, yadda yadda. There's a whole world in there.
Also: I'll be the life of the party in the nursing home.
Judo hits that too. Not so much "preventing" falls obvsly, but dealing with them. The 68yo black belt in our club is a whole lot less scared of falls than my 73yo mom, who uses a walker, is.
The point that I'm meandering around is, there are aspects of "health" beyond cardio & strength & mobility. The things that amp up your vigor & enthusiasm, that revive your eagerness; the things with a social aspect like group martial arts classes (or yoga or racquetball or square dancing or bocce ball or curling or hockey); the things with an artistic side to them like quilting (or piano or painting or carpentry or framing people for murder): those things are GOOD for you. Want to hike? Get a dog. You find something that's fun & interesting, with even a little bit of physicality to it — badminton, croquet, Ultimate Frisbee, ballroom dancing — and you've struck gold.
Fuck training for "health". Train for fun!