I remember this quote was posted on the wall of the Marine Corps physical fitness center where I worked out over 40 years ago; "Physical fitness is transitory, it must be worked for continuously, and the only program of effective value is a lifetime one."
At 62, I find it's fairly easy to stay in shape, but a real bitch to get in shape. It helps to not have been a star athlete, as those injuries from your youth come back to haunt you in later life. Good work guys, and keep it up forever. Carpe Diem.