Positive emotions may increase resistance to the common cold, according to a recent study in Psychosomatic Medicine (Vol. 65, No. 1). The research by Sheldon Cohen, PhD, of Carnegie Mellon University and colleagues adds to a body of literature that suggests that emotional styles influence health. The researchers interviewed 334 healthy volunteers by phone for seven evenings over three weeks to assess their emotional states. Participants described how they felt throughout the day in three positive-emotion areas of vigor, well-being and calm and three negative-emotion areas of depression, anxiety and hostility by rating their emotions on a scale of zero to four.
After this initial evaluation, researchers administered a shot of a rhinovirus, the germ that causes colds, into each participant's nose. Afterward, participants were observed for five days to see if they became sick and in what ways cold symptoms manifested. The volunteers were considered to have a clinical cold if they were both infected and met illness criteria.
"People who scored low on positive emotional style were three times more likely to get sick than those with high positive emotional styles," Cohen says.
The researchers then measured how emotional style affected all sick participants' reporting of cold symptoms. Each day of the quarantine, researchers asked them to report the severity of such cold symptoms as a runny nose, cough and headaches on a four-point scale.
While negative emotional style did not affect whether people developed colds, the study found that people with higher negative emotional styles reported more symptoms than expected from objective health markers, Cohen says. Those with lower positive emotions reported fewer symptoms of illness than expected.
Positive emotional style was also associated with better health practices and lower levels of epinephrine, norepinephrine and cortisol, three stress-related hormones, but the researchers found that this did not account for the link between positive emotional style and illness.
Considering the average adult catches two to five colds per year and children average seven to 10 colds per year, developing psychological risk profiles and considering ways to enhance positive emotions might reduce the risk of colds, says Cohen.
Cohen adds that future research should focus on the unique biological role that emotions play in health.