Oz offers this last tip: laughing eases stress, promotes social bonding, lowers blood pressure and it may boost the immune system.

Engage Your Brain

Researchers are learning more and more about what keeps the brain sharp over time and how it affects lifespan. Scientists say that fewer than one in 200 people reach the age of 90 with no sign of dementia, and those people are offering researchers bountiful new data on how they did it, the New York Times reported last year.

"We think, for example, that it's very important to use your brain, to keep challenging your mind, but all mental activities may not be equal," Dr. Claudia Kawas, a neurologist at the University of California, Irvine, told the Times in a May 2009 article. "We?re seeing some evidence that a social component may be crucial."

The Times article featured a group of plus-90 women who play bridge, which tests memory and keeps the brain engaged. Evidence suggests that people who spend three hours or more a day engrossed in mental activities like card games might be at reduced risk of developing dementia, the Times reported. Researchers want to know if those card players are active because they are sharp, or sharp because they are active.

But studies so far certainly suggest that it's a good idea to take your brain out for a spin every day. Do puzzles or games. Read a type of book that is unfamiliar. Learn a new skill -- a dance step or basic phrases in foreign language. Change up daily routines a bit. Or get creative -- take a stained-glass window or woodblock print art class.