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TUESDAY, July 22, 2003 (HealthDayNews) -- Want to stay healthy? Then put on a happy face.
Researchers have found that people who have more positive emotions, such as happiness and calmness, have fewer colds than glum people.
The finding appears in the July issue of Psychosomatic Medicine.
"We found that people high on positive emotional style were less likely to develop colds than people who were low," says study author Sheldon Cohen, a professor of psychology at Carnegie Mellon University in Pittsburgh.
And, he adds, "as positive emotions increase, the probability that they would develop a cold decreased." So, as you get happier and more relaxed, your chances of catching a cold are reduced even further.
"Laughter really is the best medicine," says psychiatrist Dr. Gerald Shiener of William Beaumont Hospital in Royal Oak, Mich. "Good mental health precedes good physical health."
For the study, Cohen and his colleagues recruited 334 healthy volunteers. They were between the ages of 18 and 54, with an average age of 29. One hundred and seventy-five of the volunteers were women.
At the start of the study, all of the volunteers were tested to make sure none had colds. They were then interviewed by phone three nights a week for two weeks. The researchers asked them to rate on a scale of zero to four how closely a particular emotion described how they had felt during the day. The nine positive emotions were: lively, full of pep, energetic, happy, pleased, cheerful, at ease, calm and relaxed. The nine negative emotions were: sad, depressed, unhappy, on edge, nervous, tense, hostile, resentful and angry.
The researchers then averaged the emotions from all of the interviews. People who scored high on positive emotions were said to have a positive emotional style, while people who scored high on negative emotions had a negative emotional style.
For the last week of the study, the participants were quarantined. Using nasal drops, the researchers placed a virus that causes the common cold into the volunteers' noses, and then monitored them for signs of infection and symptoms of a cold for five days.
People with positive emotional style weren't less likely to be infected with the cold germs. However, they were less likely to show any symptoms of being ill than people who scored low in positive emotional style, the researchers say.
Having a negative emotional style didn't increase the risk of getting sick, but these people tended to complain more about the symptoms they did have.
Cohen says the researchers also found people with positive emotional style had better health habits, such as exercising, eating well and getting enough sleep, and they had lower levels of three stress hormones. He says the researchers controlled for these factors and still found an association between positive emotions and fewer cold symptoms.
He explains that chemical mediators, such as histamine and pro-inflammatory cytokines, are responsible for cold symptoms. And he suspects positive emotions may dampen the production of these mediators.
So, can the power of positive thinking keep you healthy? Maybe, says Cohen, but he cautions that this study couldn't define if the people who scored high in positive emotions during this study have always been happy people, or if they were simply in a good period of their lives during the research.
Shiener says he believes people can make themselves happier. He adds that it's important that you don't keep your emotions bottled up and that you take time to do things you enjoy.
"Stress and emotions do affect our immune responses," says Shiener. "If we're comfortable and happy, then we'll live longer and healthier lives."
To read more about the "science" of happiness, visit the American Psychological Association. To learn more about helping people with depression, read this article from the American Medical Association.