The lead author of the study, which is published in the Journal of General Internal Medicine, said that based on the results, she would not encourage women to look to slow breathing as a treatment for hot flashes.

"I would actually rule this out. One of the reasons is, I think we need to not tell women to use things that are not helpful, because it delays them finding treatments that are helpful," Janet Carpenter, a professor at Indiana University's School of Nursing, told Reuters Health.

Slow breathing, also called paced respiration, involves taking six to eight breaths every minute. The method is commonly encouraged for relaxation, and is thought to regulate parts of the nervous system that control heart rate and other basic body functions.

The North American Menopause Society and many physicians encourage women to practice the technique twice a day for 15 minutes at a time, and also at the onset of a hot flash.

The approach has been appealing to women who don't want to use hormone therapy, which is considered the most effective way to treat menopause symptoms, or women who have health conditions, such as breast cancer, for whom hormones are not recommended.

Some past research has found that slow breathing can give women a measure of relief from hot flash symptoms, but those studies were either very small, conducted under unrealistic laboratory conditions or poorly designed, according to Carpenter and her colleagues.

They set out to test slow breathing in a randomized controlled trial, considered the gold-standard for medical research, by assigning some women to use the technique in their daily lives, some to practice a sham breathing technique and some to do nothing.

Of the 218 women in the study, 88 women were randomly asked to use the slow breathing approach when they experienced a hot flash. For comparison, 86 women were asked to do the opposite - take quick, shallow breaths - and another 44 were to behave as they would normally.

At eight weeks into the experiment, and then at 16 weeks in, at least some of the women in all three groups experienced fewer hot flashes per day, but there were no differences between the groups in the size of that change.

The severity of hot flashes and how much they bothered the women also decreased over time, but to roughly the same degree in each of the three groups.

For other measures of well being, the results were mixed, and none of them appeared large enough to make a difference to women's lives, Carpenter said.

For instance, negative mood worsened slightly, by less than one point on a 50-point scale, among women who did the slow breathing, while it improved slightly, by close to two points, for women who did the shallow breathing.

Carpenter said these differences were visible statistically, but in the real world, women would probably not notice such small changes.

Myra Hunter, a professor at King's College London who has studied paced respiration, said she found it to be helpful in reducing how much hot flashes bothered women.

Hunter said disparities between her own findings and Carpenter's could be because the women who used the breathing technique in her experiment also employed other cognitive and behavioral changes.

"It is possible that adding cognitive strategies strengthened the effect. Further research is needed to unpack these specific elements of these interventions," Hunter wrote in an email to Reuters Health.

Dr. Margery Gass, the executive director of the North American Menopause Society, said the new study's results support other evidence that the benefits of alternative therapies for hot flashes, if any, are modest at best.

Nonetheless, she said women can give slow breathing a try, because it doesn't have any side effects and it might help some women.

"Paced respiration, slow deep breathing, are thought to have beneficial effects to the body anyway," Gass told Reuters Health. "And if some women have benefits, that's great and if some women don't, they can move on to some other therapy."

SOURCE: bit.ly/Nqtq6o Journal of General Internal Medicine, online August 31, 2012.

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