(CBS) It's the eve of the National Day of Prayer, and on this day as on others, people are asking the Almighty for all sorts of things - from a winning lottery ticket to recovery from some dread disease. Forty-three percent of adults in the U.S. pray for their own health, according to a 2004 survey of 31,000 adults.
Is God listening?
A 2003 study showed that the death rate among people who attend religious services once a week was 25% lower than that of godless types. The study's lead author, Rush University Medical Center's Dr. Lynda Powell, told the Wall Street Journal at the time, "After seeing the data, I think I should go to church."
Churchgoers may take prayer's healing power on faith, but what does science say?
Several studies have shown a positive association between prayer and health. A 2001 study found reciting rosary prayers or yoga mantras enhanced heart rhythm and breathing, and a 2011 study published in the Journal of Behavioral Medicine linked prayer to pain relief.
Other studies have looked at so-called intercessory prayer - praying for someone else rather than oneself - and yielded provocative results. A 2001 study rocked the medical establishment by showing that women on the receiving end of prayer by Christian groups were twice as likely to have a successful pregnancy than women who weren't prayed for.
The study's findings were questioned by other researchers, the New York Times reported. And a larger 2006 study that involved more than 1,800 heart patients found prayer to be ineffective at reducing complications following heart surgery.
"One caveat is that with so many individuals receiving prayer from friends and family, as well as personal prayer, it may be impossible to disentangle the effects of study prayer from background prayer," the 2006 study's co-author, the University of Tennessee's Dr. Manoj Jain, said in a written statement.
And some scientists think research on prayer amounts to scientific sacrilege.
"Intercessory prayer presupposes some supernatural intervention that is by definition beyond the reach of science," Dr. Richard J. McNally, a Harvard psychologist, told the New York Times. "It is just a nonstarter, in my opinion, a total waste of time and money."
What do you think? Can prayer bring better health? Or is it just a waste of time?