Want to be healthy until the day you die? Laugh more, get some sleep, and get a tetanus shot. "Longevity has a strong genetic component, but how healthy you are as you age is largely up to you," says Harvey Jay Cohen, M.D., director of the Center for the Study of Aging and Human Development at Duke University in North Carolina. "Most of us want to be healthy until the end, not live to 100 and be a decrepit wreck." Cohen tells us how to go the distance in the best shape possible.

Laugh more

Numerous studies have shown that laughter can reduce stress, improve your immune system, and even relieve pain. The findings have prompted the proliferation of "laughter clubs" around the globe. Participants, many of them with chronic illnesses, gather together to laugh and do breathing exercises.