Adjust font size:

(CNN) -- Dr. Thomas Perls is the founder and director of the New England Centenarian Study, the largest study of centenarians and their families in the world.

As one of the nation's leading gerontologists, Perls also runs the Web site , which allows visitors to assess their life expectancy.

Dr. Perls shared some of the secrets of longevity with CNN.

Q: Is it safe to assume someone will live longer simply because they eat healthy, exercise and are relatively in good health?A: It is certainly safe to say that those behaviors and good health status will improve not only your life expectancy, but also help you live more of your life in good health, compressing the time you are not doing well toward the very end of your life.

Most people with good health habits, appropriate health screening and if need be, interventions, should be able to live to their mid to late 80s, much of that time independently.

Q: Tell us five action steps people could start doing immediately to prolong their life?

A:

1. Stop smoking.
2. Manage your stress, don't let it manage you. It isn't so much the amount of stress in your life that counts, but rather how well you manage it.
3. Exercise your muscles. Strength train 2-3 times a week and get some other form of exercise in, for 30 minutes a day, the other days.
4. Exercise your brain. Participate in new and difficult cognitive activities (puzzles, brain teasers, learning a musical instrument or language). This is strength training for your brain which can delay memory loss and perhaps, if you are predisposed to it, Alzheimer's disease.
5. If you don't do one or more of the above, take the life expectancy calculator at
   my Web site and it will tell you how to add years to your life.

Q: What's the connection between dental floss and longevity?A: Not flossing your teeth inevitably leads to inflamed gums. Chronic inflammation leads to the release of inflammatory substances into the bloodstream that can clog the arteries.

Q: When it comes to family history and genetics, is it possible for someone to live to 100 even if their parents or grandparents died at a young age?A: The New England Centenarian Study has shown that exceptional longevity runs very strongly in families. If you have parents, grandparents or great-grandparents who lived, say, beyond the age of 95 years, this may be very good news for you. It likely improves your chances of living to a very old age.

If such relatives partook in bad health behaviors, then you don't really know what the potential longevity is in your family. However, one thing this information does tell you, is that you certainly should not partake in the same bad behaviors since it is more likely, as a relative, that you would meet the same fate.

Q: What are some of the recurring "secrets" and practices of centenarians that you've encountered in your research?A: They are a very heterogeneous, or mixed, group and so they vary a lot. But a few preliminary findings: They tend to manage stress well; they shed the stress rather than internalize it. Smoking is incredibly rare. Obesity among the men is very rare; women can be stockier. If you're a man, it's better to be married. Women tend to do fine unmarried.

Q: Is it ever too late for people to start making changes to extend their life?A: Absolutely not. Changes you make today could immediately extend your life.