We are a commune of inquiring, skeptical, politically centrist, capitalist, anglophile, traditionalist New England Yankee humans, humanoids, and animals with many interests beyond and above politics. Each of us has had a high-school education (or GED), but all had ADD so didn't pay attention very well, especially the dogs. Each one of us does "try my best to be just like I am," and none of us enjoys working for others, including for Maggie, from whom we receive neither a nickel nor a dime. Freedom from nags, cranks, government, do-gooders, control-freaks and idiots is all that we ask for.
We're talking about general fitness and energy for life during the years of sarcopenia, arthritis, and other various age and accident-related things. Younger people can take on tougher programs but few of them do.
- 3 hrs of resistance exercises/wk: weights +/- machines. It's for muscle and bone.
- 2 hrs/wk of "cardio." Includes HIIT. Gotta challenge that heart muscle or it will give out on you. Even so, it might anyway unless some cancer kills ya.
- 2 hrs/wk of exercise class or your own calisthenics. Classes push you harder. These are for agility, athleticism, cardio, balance, endurance, etc. To make your body do what's it's meant to do.
That's a good program, because it permits space to miss a random day without losing a step. A 5-hour hill hike can be a sub for any day. What about sports, yard work, gardening, etc? Unless you are playing a few sets of tennis in the US Open, these sorts of things are why you work to stay fit. Doing ordinary life things are the rewards of fitness, but provide no fitness.
With respect, three hours a week of resistance training is far too much for both young and old.
No one could do three hours of intense weight work without damaging one's muscles, which need significant time for recovery. Read McGuff's "Body by Science" for the details. Fifteen minutes of work to temporary failure of all major muscle groups is superior in every way (including efficient use of time) to three hours of rep after rep and set after set.
From personal experience, I can say that the hardest part of this approach is pushing oneself to failure -- it takes immense concentration and it's no fun, but it produces results.