I'd kept in reasonable physical shape starting in my mid-20's, thankfully! ...with more than a few times over the years falling-off-the wagon for periods of time for various reasons.
One of the many activities I'd always enjoyed was cycling.
Dissolve to 40 some years later, retiring at 64, zero "work" distractions now...
For whatever reason, I've been enjoying cycling immensely these last few years. Now, at 66, I've found that in just a few years riding I've improved immensely. Lost weight, strength, aerobic capability.. It's amazing how we are capable of improvement even now.
No special food, no special training regimen, Just ride.. mostly by myself.. a few organised rides, ('doing the 107mi GSFondo in Sept.) Fortunately even after several long tough days of riding, each new morning I wake up with the idea that I can't wait to get out there and spin! Although the weather around here often adjusts my idea(s)
I do enjoy pushing myself with increasing distance, speed, climbing etc. Real simple plan and It's worked for me!
It's fantastic to hear of the progress you've made! Keep it up!! Adding miles, and climbing as you improve even more.