A new study suggests that happiness is good for health. Epidemiologists at University College, London, reported their results Monday in the journal Proceedings of the National Academies of Science.
Researchers Andrew Steptoe and Jane Wardle looked at data collected in a single day by the English Longitudinal Study of Aging, a large survey in England. A subset of 3,853 people, ages 52 to 79, were asked to record the extent to which they felt happy, excited, content, worried, anxious and fearful on a 1 to 4 scale at four times during the day: upon waking, 30 minutes after waking, at 7 p.m. and again upon going to bed. Their measurements of happiness, excitement and contentment combined to create a score for positive affect, or good mood. Worry, anxiety and fear ratings were combined to measure negative affect, or bad mood.
Once the researchers had their positive and negative affect scores, they divided the study subjects into three groups based on their positive affect ratings - high, medium and low - and followed up with the members of each group five years later to see who had died. In the high group, 3.6% of subjects had died; in the medium group, 4.6%; and in the low group, 7.3%.
“We had expected that we might see a link between how happy people felt over the day and their future mortality, but we were struck by how strong the effect was,” says Andrew Steptoe, the lead author of the study and a professor of psychology at University College London, in the United Kingdom.
Researchers took into consideration other factors like socioeconomic factors, initial health, depression and other health indicators. People with high positive affect still had a lower mortality rate than those who were less happy. The trend also persisted when the team removed data from subjects who died in the first six months after the survey. The authors wrote that this indicated that “effects are unlikely to be caused by seriously ill people experiencing low PA [positive affect] before death.” Negative affect did not have the same significant effect on death rates, they wrote.
What made this study different, Steptoe and Wardle wrote, was that the subjects were reporting their moods in real time, and not recollecting them later on. These ratings “provide more accurate indications of affective state,” they wrote. “The present findings provide further reason to target the positive well-being of older people.”
“There is always room for error, of course; if I get a parking ticket or stub my toe on the way to the study, I'm not going to be particularly happy,” says Pressman, who was not involved in the study but researches the impact of happiness on health. “But given that the study worked, it suggests that, on average, this day was fairly typical for the participants.”
Positive emotions could contribute to better physical health in a number of ways. Regions of the brain involved in happiness are also involved in blood-vessel function and inflammation, for instance, and studies have shown that levels of the stress hormone cortisol tend to rise and fall with emotion. “We would not advocate from this study that trying to be happier would have direct health benefits,” Steptoe said.
The authors received funding from the British Heart Foundation, Cancer Research UK, and the (U.S.) National Institute on Aging.
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