Sex has to do with imagination, so the sky is the limit. If you're not doing bodily harm, why shouldn't you do what turns you on?

Ask the guys who are doing serious triathlons if there are any limits to what can be done. The limit is right here. You've got to get physically fit between the ears. Muscles don't know anything. They have to be taught.

Sometimes people - especially people over 40 - underestimate what they really are capable of. They believe they're not capable of doing something great. I tell people who are over 40, "I don't want your best. I want better than that. I want better than what you perceive your best is."

Many so-called spiritual people, they overeat, drink too much, they smoke and don't exercise. But they do go to church every week and pray 'Please help my arthritis. Please help me bring up my strength, make me young again.'

You start out with an hour on the treadmill, then another hour of lifting - hell, in two weeks you're not doing anything anymore. You gotta be reasonable.

When I first started out, I was considered a crackpot. The doctors used to say, "Don't go to that Jack LaLanne, you'll get hemorrhoids, you won't get an erection, you women will look like men, you athletes will get muscle-bound -- this is what I had to go through.

You should do it against the clock. Say you are going to do 30 laps in 15 minutes. Then you try to do it each day a little faster. That is putting demands on the body, and that is how you build up. You keep up your energy instead of going downhill.