Living a longer life: whose advice helps?

The father of fitness, Jack LaLanne advocated exercise and weight training long before they were in vogue. He was among the first to encourage women to lift weights -- and to dispel the misconception that it would make them look masculine. He opened his first health spa, in Oakland, in 1936, and later had more than 200 health clubs. For 34 years, from 1951 to 1985, he hosted "The Jack LaLanne Show," a popular TV fitness show that aired throughout the United States and Canada.

At age 42, he set a Guinness world record for fastest completion of of 1,000 push-ups (23 minutes). At age 60, he swam from Alcatraz to Fisherman's Wharf while handcuffed, shackled and towing a 1,000-pound boat.

He has defined age as not being able to do things you used to, saying people can ward off age, reverse it and prolong life through exercise. If exercise can help you do things you haven't been able to do in 10 years, it's rejuvenating, he says. His longevity advice boils down to weight training, aerobic activity, plus a good diet that includes a lot of fruits and vegetables. His book "Revitalize Your Life" touts his "secrets" to reversing aging and living longer, and remains a top seller in its genre. "Live Young Forever," which is due out in September, promises "12 Steps to Optimum Fitness, Health and Longevity."

Today, at 94, LaLanne still works out two hours a day lifting weights and swimming.

The verdict: "I love Jack LaLanne," says Tom Perls, a geriatrician and director of the New England Centenarian Study, "he's living proof of the saying: 'The older you get, the healthier you've been.' "

Adds Olshansky: "He was way ahead of his time. . . . Decades ago, he was onto the most important ways we can influence aging, by exercising and eating fruits and vegetables."

Nathan Pritikin

1915-85

After being diagnosed with heart disease in the 1950s, Nathan Pritikin, an engineer, got this advice from his doctor: Take it easy, don't overexert yourself and keep eating the American diet of eggs, beef and the like.

He didn't buy it. Instead, he began studying cultures that had low rates of heart disease -- and created his own diet. The resulting Pritikin Program advocated regular exercise and a low-fat, high-fiber diet as a way to improve health, prevent heart attacks and extend life. Pritikin also outspokenly recommended that heart doctors focus more on nutrition and exercise, and less on drugs and surgery. His appearances on CBS' "60 Minutes" in 1977 and 1978 brought this then-new message to the public.