40 and the fittest i have ever been, and i have always been active. Most people thst conplain about old sge in their 40s are just living s horrible éige of zero exercise and bad diet. The fittest people i know are all in the ir 40s and 50s, and plenty of people in their 60s sre far faster than me in my races (ultras).
i do need to pee in the night but it 100% down to coffee and or alcohol. I tend to detox regularly before competitions or hesvy training and i cut almost all coffee and alcohol, then i sleep like a log all night 9-10 hours.
1 simple trick is simply to have 1 coffee early in the morning. It wont impact much by the evening.
Weight gain doesn't change, thsh is purely calories in vs out, whatever some internet based pseudo-science diet suggests.
This, I'm in my 40s and fitter than I've ever been. A lot of my mates are just becoming increasingly lardy and racking up health problems. You can't keep living the same lifestyle once you get older and expect to get away with it. Frankly I've done all the boozing, drugs, partying and hangovers I need for a single lifetime....so spending my time doing physical activities is much more enjoyable. Besides that, hangovers last a week now!
In the last week I've been outdoor trad climbing three times, outdoor bouldering once, outdoor sport climbing once, and indoor bouldering once.....and off to Scotland next week for a week of mountaineering.
Still have some age-related niggles. Osteoarthritis and bone spurs in my big toes. Muscle tear in my back that never healed properly (which can be managed). Gave up on the hair years ago
OP may want to talk to GP about peeing and prostate issues....there are a number of causes ranging from cancer, bacterial infection, to random age-related prostate swelling. I've been having issues, had PSA test and stuff so unlikely to be cancer, still dealing with GP though.