"I don't care if people are 80 or 85 when they start," he said. "They can double their strength and double their endurance in six weeks. You won't be able to do what you could when you were 20, but do the best you can with the equipment you have."

LaLanne has slowed down in recent years, but suffers no joint pain and only occasional muscle aches. He's had two knee replacements - from football and car crash injuries, not exercise. He's never taken steroids, but did develop his own line of vitamins and of course, his juicer, made famous on late-night infomercials.…

"Working out three or four times a week is plenty for most people, but it's an ego thing with me," he said of his regimen. "I'd like to see how long I can keep it up."

In his prime, he could lift two 150-pound dumbbells doing chest presses and set a record of 1,033 pushups in 23 minutes at age 42.