PerspectivePsychology

Happy People Live Longer

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Science  04 Feb 2011:
Vol. 331, Issue 6017, pp. 542-543
DOI: 10.1126/science.1201060

There is a longstanding idea that happiness causes people to live longer, healthier lives. However, convincing evidence that subjective well-being (the more scholarly term for happiness) contributes to longevity and health has not been available. Recently, however, social psychologists Diener and Chan (1) showed that many kinds of studies, using different methods, conclude that happiness has a positive causal effect on longevity and physiological health.

Previous studies had offered widely different and competing findings. Some found no causation or reverse causation, in particular that healthy people are happier (which is undisputed) (2). Others suggested that unidentified, unobserved factors influence both happiness and longevity and health. Diener and Chan's survey presents solid evidence for the benefits of happiness. For example, a meta-analysis (3) based on 24 studies estimated that happy people live 14% longer than persons who report that they are unhappy. In a survey of people living in industrial countries, happier people enjoy an increased longevity of between 7.5 and 10 years (4). Happier people are also less likely to commit suicide, and they are less often the victims of accidents.

How can researchers measure the influence of happiness on physical health and longevity? One important method is the longitudinal study, in which investigators follow individuals over many years, to identify whether the happier ones live longer. The “nun study” (5) has become particularly famous. Nuns are well suited for a longevity study because they live under very similar conditions. Before young women entered a monastery, researchers asked them about their subjective happiness level. Those who perceived themselves to be happier died at a median age of 93.5 years. In contrast, those who considered themselves to be less happy died at a median age of 86.6 years.

Happy?

Satisfaction is linked to healthier, longer lives.

CREDIT: ZOOMSTUDIO/ISTOCKPHOTO.COM

Researchers can also examine how external, or exogenous, factors that induce changes in happiness are related to specific physiological processes known to affect health and longevity. Emotions can be manipulated in laboratory experiments, for instance, by showing subjects a joyful or a sad film. Investigators can then measure how particular physiological factors, such as blood pressure, change. The effect on happiness of naturally occurring events, such as tempests, inundations, and earthquakes, also can be analyzed. Researchers also study how personal shocks, such as losing a companion, affect health. For example, one study (6) finds that the mortality of men who lose their wives doubles in the first month after the event. For women, the mortality rate after losing their husbands is three times higher than normal. So far, however, an effect of happiness on specific types of illness has not been established. In particular, Diener and Chan note that studies that have explored how happiness influences the outcomes of cases of metastatic cancer have produced findings that are unclear and unconvincing.

Philosophers such as Aristotle consider happiness to be the major goal most people aspire to in life (7, 8). The findings discussed here make the pursuit of happiness even more important, since they demonstrate that high measures of life satisfaction and positive emotions strongly contribute to better health and a longer life. Future research needs to focus in more depth on the processes causing happy people to live longer and to be in better health. In addition, the costs of raising happiness by policy interventions should be compared to the costs of influencing longevity and health by other pathways.

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