Excellent summary on the mental and physical benefits of exertion: The New Science of Exercise:
Doctors, researchers, scientists--even ancient philosophers--have long claimed exercise works like a miracle drug. Now they have proof.
As I have said before, a rigorous exercise program might not extend your life. It will definitely enhance and extend your quality of life even if you begin it at any age. Everybody knows that they ought to do it, but it's hard and it hurts and we're lazy and "busy." Plus there is that terrible part: delayed gratification. Everybody hates that. As I say, "The flesh is willing but the spirit is weak."
Our quite well-informed recommendations for general fitness and conditioning for the ordinary person who wants to achieve or maintain maximal functionality for life:
1. Nutrition: Don't be visibly overweight - it's the worst thing you can do to yourself besides being an addict, and no exercise can help being fat. Does a demanding exercise program require a specific pattern of nutrition? Yes. We have discussed that in previous posts here. With a serious exercise program, you have to keep up with the protein and fats - approx. 70-90 gms of protein/day.
2. Weight training - as heavy as possible, approx 50 minutes twice a week
3. 1-2 hrs total of calisthenics/wk for mobility, balance, and athleticism
4. 2 or 3 twenty-min sessions of cardio intervals/wk (HIIT). (For HIIT, I do stairs once, elliptical once, rowing once. Occasionally sprints in the pool.) Can add an hour of endurance cardio.
Under age 35, it can take 12 months to be whipped into decent shape. Over 35-40, depending on your fitness starting point, 18-24 months. Intense sports like basketball can substitute for calisthenics. Yoga is excellent, but does not substitute for any of the above. Many men find Yoga to be quite challenging and helpful. Lots of pro football players do it. If your day job is physical, all of the above recommendations would differ.
Lots of them in our border (mostly) perennial beds now. 
Posting will generally be light this holiday weekend. 
AVI: 
