But past middle age, it becomes critically important. Once your muscles, joints, and bones begin to weaken, keeping muscle mass can mean the difference between maintaining balance or not, breaking bones in a fall or not, and retaining motor function or not. It has all kinds of second order effects on general health and longevity.
I'd hardly ever get an endorphin rush/hit from cycling, but I get them regularly from weights. They certainly help the mind settle, even after a short stint.
My best tip would be to get your own equipment, if possible, to have the ability to do it frequently and without making it a mission to go to the gym.
It's amazing what you can do with a squat rack, bar bell, a bench, and a set of plates. (Starting strength / Rippetoe, Stronglifts 5x5, etc).
Weight is in fact regulating itself somewhat naturally as a consequence, but just being able to feel the body getting stronger is the real pleasure. I've been doing this for a good few months now and I know I'm adding years if not decades to my usable life span as well.
The exercise was a great stress relief for me, and I went from 165 lbs to about 215 lbs over 3 years, all lean muscle mass. Felt great. Was biking thousands of miles per year, running about 4:30 mile on the treadmill, and squatting 2x my bodyweight. I had a resting heart rate of around 45 bmp.
Then, I got hit by a car while on my bike (guy ran a stop sign and and clipped my rear wheel and seat stay). Destroyed my bike; the carbon fiber frame was cracked, carbon pedals ruined and my handle bars were messed up. I also racked up $20k in ER bills that his insurance paid. I dont know how much the X-ray, MRI and orthopaedic visits cost (his insurance had accepted responsibility at that point, and I never saw a bill). I didnt break any bones, but strained almost all ligaments in both knees. The accident knocked me off my workout schedule for 2 months while I recovered. Despite my best efforts, I was never able to reestablish my routine. I now weigh less than when I graduated high school at nearly 40. And, to boot, I suffer from arthritis now and exercising is near impossible for me now without great risk of being laid up in bed with a severe pinched nerve.
Just about everyone - even people who think they train seriously - will never, ever reach this point.
Just ride the slow and steady gain train until you actually need medically prescribed TRT.