03/22/2011 07:36 pm ET Updated May 25, 2011

How Prayer Leads To Better Health and Longer Life

People often ask me if praying leads to better health and longer life. For the past 20 years, my colleague Dr. Leslie Martin and I have been studying the religious beliefs, the personalities, the social relationships, the habits and the careers of more than 1,500 Californians who were first studied as children in 1921. They have been followed continuously for their whole lives, and we have been examining the eight decades of data to see who thrives and lives long, and who falters and succumbs by middle age. We report the surprising findings in our book, The Longevity Project, where one focus is on religiosity.

I used to wonder why people would turn to a scientist to ask a question about the supernatural -- does praying extend life? There is of course an intellectual problem involved, and scholarly interest in such matters traces back several hundred years to the philosopher David Hume, who wrote about the reasoning and evidence needed to establish the existence of miracles. But these days, I think people ask about prayer because the "science" of modern medicine is often too quick to reduce health to simple mechanical cause-and-effect relations, and so many patients feel a dissatisfaction and frustration with sterile medical care that sidesteps the human spirit.

Lots of studies show that religious people tend to live longer, but the studies usually have little idea why. (An obvious exception -- where the reason is clear -- involves those rare cases that examine non-smoking religious groups.) Because we cannot randomly assign individuals to an experiment in which some are religious and some are not, the best study would be one that follows people throughout their lives, measuring their religiosity and other characteristics. This is what we did; it is the first such study ever done. At various points in their lives, from childhood on, the participants reported on their religious instruction, their Bible reading, their worship, the extent to which they were religiously inclined, and much more.

Our findings confirmed that individuals who were religious, especially women, were more likely to live longer lives. But why? The very religious women tended to be quite friendly and sociable, but were also inclined to be worriers. We found that we could explain their long lives by taking into account their outgoing-yet-worrying personalities, and their good, helpful social ties and behaviors. In other words, for these individuals, religion was a core and stable part of who they were and how they behaved -- and it served them well in terms of long life. But there was more!

It was the least religious women who were, on average, least likely to live a very long life. These women were not religious in young adulthood and stayed that way throughout their lives. They were generally bright and productive but they were less likely to be very extroverted and trusting, less likely to get and stay married, and less likely to have children or to be extensively involved in helping others. Herein lay the core of our striking finding: overall it was not religiosity per se that was so important to long life, although it helped many women. Rather it was the characteristics that tended to go along with being religious that explained why these women lived longer. Those who gradually left their religious involvement were at high risk if they also let their community involvement falter and diminish. We found that the social engagement that is so much a part of religious community is one key explanation for the health of many religious people. Yes, those who prayed together, stayed together, and helped each other stay healthy. Naturally, many people found deep social ties and a meaningful community outside religion, and they thrived as well.

What about spirituality? We did uncover various hints of the health importance of a deeper meaning in life. Of course, many people live a consequential, purposeful life outside of any religious context; but many others find such meaning through religious wisdom. In The Longevity Project, we profile a man, Douglas Kelly, for whom meaning was everything. Kelly worked for the U.S. Army in 1946 evaluating some of the highest-ranking Nazis in preparation for their war-crimes trials in Nuremberg. But evidently, this life-changing experience with horror shattered Kelly's sense of agency and meaning, and he met a shocking early death. Those who developed catastrophizing, negative thought patterns were inclined to precipitous actions, injuries, accidents, suicides and related risks.

While we cannot provide empirical confirmation about whether being pious is important to gaining eternal life, The Longevity Project did uncover good evidence that at least some aspects of congregational participation can be relevant to the length of one's mortal life. It was the social involvement and service to others that went along with being religious that explained why these people, especially the religious women, lived longer. You may have heard the old saw that says, "The best of Men cannot suspend their Fate; The Good die early, and the Bad die late." This turned out to be myth! Instead, we sum it all up by saying, "It is the Good ones who can actually help shape their fate; The Bad die early, and the Good do great!"