People might be able to influence their immune systems by practicing certain breathing techniques in combination with spending time in low temperatures, a new study finds.
In the study, men who participated in a regimen of deep breathing and swimming in ice-cold water showed a less inflammatory response than men in a control group, whose immune system reacted to a harmless injection.
"Training was quite demanding for the participants," said study researcher Dr. Peter Pickkers, a professor of experimental intensive-care medicine at Radboud University in the Netherlands. "This is not something you want to try at home. You need proper supervision in this training." In fact, the regimen could even be harmful to some patients, he said.
But the study demonstrates the idea that people's behavior can alter their immune response and reduce inflammation. Researchers think that an overactive immune response may be unhealthy, and that the chronic inflammation it can cause may lead to autoimmune diseases, such as rheumatoid arthritis.
Although it is possible to modify the immune response with drugs, the researchers wanted to know whether certain behaviors could change it as well. In the study, the researchers randomly divided 24 healthy young men into two groups. Under the supervision of doctors, one group was trained to perform an extremely challenging regimen of breathing techniques, meditation and swimming in ice-cold water, and those in the second group didn't practice these techniques and served as controls.
After about 10 days of training, the researchers injected all of the participants with dead E. coli bacteria, which usually tricks the body into responding as if it were being invaded by living bacteria and results in an immune response to combat the pathogen.
The results showed that the trained participants produced more of the hormone adrenaline, showed less inflammation and experienced fewer flulike symptoms than the participants who did not receive any training. [11 Surprising Facts About the Immune System]
"The adrenaline level went up really high in the participants who were trained and practiced the breathing techniques — much higher than the control group — and that led to the suppression of their immune response," said study author Matthijs Kox, who is also a researcher at the medical center.
Usually, people's adrenaline levels increase in fearful, "fight-or-flight" situations — for example, when they are scared during a horror movie, or are bungee jumping. Previous studies of the effects of increased adrenaline on people's immune response have involved injecting the hormone into people, and have showed it suppresses people's immune response.
"But it's new and unique," in the new study, "that you can willingly increase it, without having to inject anything," Kox said.
In the men in the study, "the adrenaline levels were higher than in people who bungee jumped for the first time," he told Live Science.
Although the experiment showed that it is, indeed, possible to voluntarily influence the immune response, it doesn't mean that this would be healthy for everyone, the researchers said.
"We used this model as a way to measure the immune response," Pickkers said. "We cannot make any claims if there's any benefit for these participants if they had real infection or another disease."
The combination of breathing, meditation and cold exposure used in the study was adapted from methods of the "Iceman" Wim Hof, an adventurer in the Netherlands who holds world records for withstanding extremely cold temperatures.
It is unclear which one of the techniques, or which combination of them, is actually responsible for the effects on the immune response seen in the study. Nevertheless, it is likely that the breathing techniques mainly accounted for the changes in adrenaline levels by affecting the blood's acidity and oxygen content, the researchers said.
"The acid-base balance [of the blood] and oxygen levels that shifted from high to low repeatedly during the cycles of the breathing technique might have induced a kind of chemical stress, which could lead to this effect," Kox said.
The researchers said they plan to do future studies in patients with chronic autoimmune diseases, to see if these techniques can have any benefits.
"Should patients with rheumatic diseases start doing these techniques? The answer is a very clear 'no,'" Pickkers said. "People shouldn't start doing this, and definitely not instead of taking their medication — it would be dangerous."
The researchers detailed their study today (May 5) in the journal Proceedings of the National Academy of Sciences