I'm 76, retired for 20 years, and fitness is a year round, non-stop routine. Has been for most of my life. 3 days/week on road bike, 3 days/week in gym. 1 day of rest. Plenty of squats and fairly heavy (for me) dumbbell work along with some machines. Full body stuff. I finally broke down a couple of years ago and bought an e-bike. Best move ever. Former 10-15 mile rides now 20-25. My wife is similar. We can go from bell to bell still and still do the trees and bumps. But the older you get, the harder you have to work to maintain the same fitness level. Plus we've been lucky with injuries and medical issues.