Sci. Aging Knowl. Environ., 27 April 2005
Optimistic for Longevity
High spirits reduce numbers of disease-linked molecules
R. John Davenporthttp://sageke.sciencemag.org/cgi/content/full/2005/17/nf33
Turn that frown upside-down, and you might live longer. Happier people have smaller quantities of two compounds connected with heart disease, diabetes, and other illnesses, new work reveals. The results mesh with the notion that folks with sunny dispositions enjoy better health than do those with a dark outlook and suggest a biological mechanism for that protection.
People with depression die younger and are more likely to suffer from heart disease and diabetes. But researchers aren't sure whether folks with sunny dispositions are healthier than gloomy but nondepressed people. A positive outlook might provide extra protection, or everyone who's not depressed might be equally healthy. In addition, how cheerfulness would bestow health is unclear. In new work, psychobiologist Andrew Steptoe of University College London and colleagues assessed happiness and measured disease-associated molecules in human subjects.
First, the team monitored 200 middle-aged subjects for 1 day as they went about their normal activities. Every 20 minutes, a wearable device automatically recorded the subjects' blood pressures and heart rates. At the same time, individuals graded their happiness on a five-point scale. Researchers collected saliva samples eight times during the day and measured quantities of cortisol, a stress hormone that contributes to heart disease, obesity, and other diseases. The researchers grouped participants into five clusters according to the percentage of time that they reported feeling happy. Those in the cheeriest group produced 32% less cortisol than did the unhappiest people. Blood pressure did not vary among the groups, and women's heart rates did not vary with happiness. But happy men had slower heart rates than did unhappy men, an additional hint of better health.
Next, subjects performed stressful mental exercises in the lab, such as repeatedly tracing a shape under time pressure. Steptoe's team collected blood samples before and after the tests and measured the concentration of fibrinogen, an inflammatory molecule involved in blood clotting that increases the risk for heart disease. For all subjects, fibrinogen quantities rose during the stress test. But the amount soared 10 times higher in unhappy subjects compared with happy folks. Together, the results suggest that a bright mood could preserve health by minimizing the production of disease-sparking molecules. To complete the story, the team is continuing the study to find out whether happy individuals with small amounts of fibrinogen and cortisol avoid chronic illnesses such as heart disease, says Steptoe.
"It's an important finding," says psychologist Paul Costa of the National Institute on Aging in Baltimore, Maryland. "What the study is showing is that [happiness and unhappiness] are related to interesting biological pathways." To extend the results, he says he'd like to see the experiments repeated using more sophisticated psychological assessments to understand what "personality profiles might be driving the results." In addition, he'd like to know whether the connection between happiness and the biological markers persist over longer periods of time. If they do, says Steptoe, relatively small differences between groups could compound over years or decades to hasten disease. Then all we'd need is a happy pill.
April 27, 2005
Science of Aging Knowledge Environment. ISSN 1539-6150