"Nothing makes one grow old as fast as hardening of the heart."

The saying refers not to the physical phenomenon of clogged arteries, but to the age-accelerating health harms that can come from losing faith in life's goodness.

Research confirms the health advantages of a positive state of mind, connection to others and belief in some sort of higher power.

"With all of the emphasis on diet, exercise and other health behaviors, the real marker of long life seems to be mental even more than physiological," says aging expert Daniel Perry, noting that those who reach very old age "have a certain toughness of spirit about them and an ability to roll with life's punches and keep plugging away with a sense of purpose."

Religion is among the factors that have been extensively studied. People who attend religious services are healthier, live longer and become less depressed as a result of illness, according to most studies, and they handle stress better.

Because studies are generally done on groups of people who attend worship services, it is not clear whether the healing power of religion is based on greater hope (which in turn boosts immunity); a calm that decreases muscle tension and slows the heart rate; or the social support systems that can go hand-in-hand with involvement in a religious group.

Other factors that have been shown to slow the aging process include:

  • A happy marriage or long-term relationship
  • A satisfying job
  • A regular work/daily routine
  • Fun hobbies
  • A feeling of financial security
  • The ability to express feelings openly
  • Close friends
  • The ability to laugh easily
  • A satisfactory sex life
  • An optimistic outlook on the future

If choosing a pet seems simpler than searching for a spouse, take heart. Scientific studies have revealed that pet companionship, like human fellowship, has health benefits: lower heart rate, decreased blood pressure, and decreased incidence of depression and anxiety.

"Don't worry, Be happy" is more than just an expression, says cardiologist and anti-aging doctor Stephen Sinatra, M.D. It's simple, he adds: "If you're an optimistic person, you'll live a healthier and longer life."