THURSDAY, July 12 (HealthDay News) -- New research suggests that regular exercise or meditation may be among the best ways to reduce acute respiratory infections.

A small study of 149 active and sedentary adults aged 50 years and older compared the preventive effects of moderate exercise and mindful meditation on the severity of respiratory infections, such as cold and flu, during a full winter season in Wisconsin.

The researchers found that those participants who started a daily exercise routine had fewer bouts of respiratory infections and missed fewer days of work. The investigators also found that those doing mindfulness meditation, which focuses on paying attention to your body and emotions, were more protected against illness.

The study was published in the July/August issue of the Annals of Family Medicine.

"The results are remarkable; we saw a 40 to 50 percent reduction in respiratory infections," said Dr. Bruce Barrett, an associate professor of family medicine at the University of Wisconsin-Madison and the lead author of the study.

"When we give flu vaccines, which is one of the most well-proven and beneficial interventions that we have, it only protects at a level of 50 to 60 percent and only for a few strains of [flu] virus," Barrett added. However, he noted, it could be more difficult for some people to get regular exercise or practice meditation than to get a single flu shot.

It was not clear how physical and mental workouts could help ward off sickness. While the study uncovered an association between the mind and body activities and less illness, it did not prove a cause-and-effect relationship.

"My thinking is that mindfulness meditation would reduce perceived stress and that exercise would work through more physiological pathways [to improve] the immune system," Barrett said.

The flu virus is associated with about 36,000 deaths and half a million hospitalizations in the United States every year, the study authors noted. And illnesses caused by other viruses, such as the one responsible for the common cold, are to blame for 40 million days of missed work and school every year.

The study involved mostly white women who were not already meditating or doing moderate exercise more than once a week. They were randomly broken into three groups: one-third did not change their habits; one-third started an eight-week program of moderate exercise, such as running on a treadmill and biking, for 45 minutes a day with weekly training sessions; the rest spent the same amount of time in mindfulness meditation, which included yoga, stretching, walking and other activities with an instructor and on their own.

The researchers followed the participants for one cold and flu season and asked them to call at the first sign of an illness and keep a diary of their symptoms.

During the season, the results showed, those who meditated had 27 episodes of acute respiratory illness and a combined total of 257 days of illness; those who exercised had 241 sick days and 26 episodes. That compared to 40 episodes and 453 sick days for those who did not change their habits.

The meditation group lost 16 days of work to illness, the exercise group lost 32, and the group that did not change their habits missed 67 days. But the difference was only large enough to be considered meaningful for the relationship between meditation and missed work, according to statistical requirements that the authors set before the study started.

Nonetheless, the numbers all suggested that exercise and meditation reduce respiratory illness, Barrett said. "This trial convinced me that they worked," he added.

The study also suggested that, although the benefits of meditation and exercise were similar, when individuals in the meditation group did fall ill, they seemed to suffer less and feel sick for less amount of time.

"This study is a really useful addition to the literature," said James Carmody, who has studied meditation and chronic illness at the University of Massachusetts Medical School in Worcester.

Research has found that mindfulness training reliably affects the way people perceive their symptoms of illness and reduces stress, Carmody said, although there is less evidence that their bodies actually respond differently to infections.

"If I can redirect my attention and not have it so compelled by the runny nose or the sore throat, I'm going to be less bothered by colds," Carmody added.

David Nieman, a professor of exercise science at Appalachian State University, thinks that both exercise and meditation might make people less susceptible to illness by reducing their stress levels.

But the benefits of exercise are fleeting, he added. His own research found that people who exercised five days a week had the largest reduction in cold symptoms, while those that exercised only a few days a week had intermediary benefits.

More information

To learn more about meditation practices and health, visit the U.S. National Center for Complementary and Alternative Medicine.

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