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Literature That You May Have Missed

A regular contribution from Lars Ovesen, which we hope will help the busy scientist keep up with the literature: The Power of Prayer

Ovesen, Lars

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European Journal of Cancer Prevention: February 2001 - Volume 10 - Issue 1 - p 121-122
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A British tar was asked by a French sailor why the British Navy always was victorious.

‘That's easy to answer,’ replied the Briton. ‘We always pray before we start fighting’.

‘But so do we,’ retorted the Frenchman.

‘Yes,’ came the rejoinder, ‘But we pray in English.’

Studies, largely unknown to the public and to scientists, have examined the therapeutic efficacy of prayer. Notable is the pioneering work by Sir Frances Galton more than a century ago (Galton, 1872). Galton examined the frequency with which ships that carried missionaries experienced disaster at sea and compared this with the frequency of disasters experienced by ships not carrying missionaries. He found that missionary ships sank with a frequency and loss of life slightly greater than that of less-blessed ships. Galton also found that the mean life-span of humble clerical males who had survived their 30th year was not longer than the life span of the – at that time – extremely materialistic lawyers and doctors. To substantiate his claims of the inefficiency of prayer on longevity, Galton cites work by Guy who considered that ‘of all classes of society in England those most prayed for were the sovereigns and the children of the clergy.’ So, if prayer is effective, they should experience very long lives. So Kings were compared with Lords, and the children of the clergy with those of other professional men. Galton also astutely directs our attention to the fact that if prayer was efficacious with respect to longevity, insurance offices would long ago have discovered it and made allowance for it. The conclusion from the studies of Galton was that those much prayed for were not blessed with a long life but in contrast had slightly shorter life than those not prayed for.

This conclusion was derived at in the old days. Today the efficacy of prayer has been tested with modern and more rigorous scientific methods. This has been done in many studies; however, only a few will be mentioned here.

The first study was performed among patients with chronic diseases, half of whom were prayed for and half not prayed for (Joyce and Welldon, 1965). The praying was performed by six prayer groups, and each patient received a total of 15 h of prayer during a minimum of 6 months. The patients were unaware that a trial was in progress, the prayer groups did not meet with the patients, and the praying was conducted at least 30 miles away from the patients. The type of prayer consisted of mentally imaging the patient and thinking of the patient in the context of the love and wholeness of God, called ‘the practice of the presence of God’. The study found no beneficial effect of prayer on clinical state. Likewise, in another blinded study of leukaemic children, those prayed for daily in a Protestant church, did not have better survival or clinical status than the children not prayed for (Collipp, 1969).

A more recent study examined the effect of praying to the Judeo–Christian God on the medical condition of patients admitted to a coronary care unit (Byrd, 1988). The patients were divided randomly into a group prayed for and a group not prayed for. The study was performed double blind – i.e. the patients (and the doctors and other healthcare personnel) did not know if they were prayed for – and the prayers, who were ‘Born again Christians’ with an active Christian life, did not know to whom the prayers were addressed. It was assumed that some of the patients in the group who did not receive the ‘active’ prayer were prayed for by other people not associated with the study, although it was not possible to control for this. Each patient was assigned to between three and seven prayers and the praying demonstrated that the group prayed for had fewer complications – less heart failure, required less diuretic and antibiotic therapy, fewer cardiac arrests, and less frequently required intubation and ventilation – than the group not prayed for. No side effects of prayer were encountered. How the prayer works is unknown. Was it God at work? And if so, were the groups treated by God as a whole or were individual prayers alone answered?

Although no side effects have been observed with acute praying, chronic praying may increase the risk of obesity. This has been demonstrated in a study from the USA, which found that obesity was higher in states with a higher proportion of persons claiming a religious affiliation, and in states with a higher proportion of Baptists (Ferraro, 1998). People who were more active in practising their religion were more likely to be overweight. As the author rightly points out ‘firm believers do not have firm bodies’. There was no evidence from the survey that religion operates to intensify or mitigate the negative effect of deviant body weight on well-being.


1. Byrd RC ( 1988 ). Positive therapeutic effects of intercessary prayer in a coronary care unit population . South Med J 81 : 826 – 829 .
2. Collipp PJ ( 1969 ). The efficacy of prayer: a triple blind study . Medical Times 97 : 201 – 204 .
3. Ferraro KF ( 1998 ). Firm believers? Religion, body weight, and well-being . Rev Relig Res 39 : 224 – 244 .
4. Galton F ( 1872 ). Statistical inquiries into the efficacy of prayer . Fortnightly Review 12 : 125 – 135 .
5. Joyce CRB , Welldon RMC ( 1965 ). The objective efficacy of prayer. A double-blind clinical trial . J Chron Dis 18 : 367 – 377 .
© 2001 Lippincott Williams & Wilkins, Inc.