Happy people are three times less likely to get a cold, according to researchers who squirted cold virus up the noses of volunteers.

Psychologist Sheldon Cohen and his colleagues at Carnegie Mellon University, Pennsylvania, also found that the positive thinkers who do develop symptoms complain about them less.

The team studied over 300 initially healthy volunteers. First, each person was interviewed over two weeks to gauge his or her emotional state. This involved being scored in both positive categories – happy, pleased, relaxed – and negative categories -anxious, hostile and depressed.

Next the researchers squirted rhinovirus, the germ that causes colds, into each subject’s nose. Follow-up interviews questioned them daily for five days about any developing symptoms.

The people scoring in the bottom third for positive emotions were three times more likely to catch a cold that those scoring in the top third. ”People who express more positive emotions are less susceptible to upper respiratory tract infections than people with a negative emotional style,” says Cohen. Intriguingly, the scores for negative emotions showed no correlation with infections.

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