Yes it is. I’m 59 and wow it hit me like a ton of bricks a few years ago. Not exercising throughout my 20s, 30s and 40s were no problem but once I hit 55 all kinds of hell started. Bad knees, back problems, weak legs, sleep apnea, chest pains, so I started just that: Weight training and jogging and my God EVERYTHING improved, everything. I feel no different from when I was 20, absolutely no pain anywhere, no sleep problems, and things just seem sharper, more aware. Exercise is so insanely important when you get older otherwise everything falls apart.
You bet. I'm 80 and still do 100 push ups every day {not continuously, but 10 at a time} and feel like I'm cheating on life when I don't {or because of surgery can't}.
I really re-started when I turned 50 because that's when the wheels began to fall off.
I have friends my age that wonder what the secret is and when I tell them...they either don't believe me or don't want to do the work, because they never do.
When I quit doing it, I'm done with life.
I’m 64 and have exercised 3-6x/wk since I joined the Air Force in 1985. I retired 6 years ago and have kept it up. It’s likely that the heart attack on Easter morning 2019 would have happened much sooner and been much worse if I had been sedentary all those years. 11 stents later I’m still on the bike and on the weights.