As I wrote in my book "False Alarm; the Truth About the Epidemic of Fear," our primary fear as human beings is a fear of death. This fear is manifested by a daily fear of losing control of our lives (this is why we all like our little routines to keep us on track), and a growing fear as we get older, of losing our good health.

Many of my patients worry that each symptom they experience, from a twitch or a cough to a fever, could be the initial sign of that larger unraveling of life that we all dread.

I spend most of my day in the office reassuring my patients that this isn’t the case; that they are healthier than they think, that they are nowhere close to doom.

I’ve also discovered that buffers against illness like exercise, good sleep, and diet help people focus on something other than their personal clock ticking down. There is a vicious cycle; the more stressed out and worried we are the worse our health becomes. The more we can have fun, laugh and relax the better our chances for good health.

We rely on our celebrities and our role models in the media to help us perpetuate the illusion of good health -- and a hope that it will last forever.

This perception helps us get through the day. It's why we get so disturbed when one of our personal favorites, be it Whitney Houston or Michael Jackson or Patrick Swayze, meets an untimely end.

It is why we smile when we see the unexpected recovery of Dick Cheney or the baseball pitcher Andy Petite coming out of retirement to return to the mound.

For a moment we feel as if our own healthy time on this planet has been extended.

Don’t get me wrong; our health is fragile, and it is precious. You can be in the flush of life one minute, and faced with the threat of death the next. This can happen at age 48 just as it can happen at 88.

But this type of personal tragedy is much less likely to happen if we live good, clean lives, exercise regularly, sleep well, keep our weight down, and stick to a diet of mainly fruit, veggies, and protein. Most of us in America don’t do that but we should.

The lesson from a celebrity’s sudden death or watching a loved one suddenly cut down in the prime of life is not that we are all on the verge of an untimely death that we need to always live in fear from, but rather that we can likely avoid this kind of harrowing end for at least a long time by living right.

Marc Siegel, M.D. is a professor of medicine and medical director of Doctor Radio at NYU Langone Medical Center. He is a member of the Fox News Medical A team and author of several books. His latest book is "The Inner Pulse; Unlocking the Secret Code of Sickness and Health."