The Why Files -- whyfiles.org

Happy to be healthy

Photo: Mike Baird.

Being healthy is a key to being happy, but new research shows that the opposite relationship may also hold.

In a study showing how mind can dominate matter, Mohammad Siahpush, a professor of health promotion at the University of Nebraska Medical Center in Omaha, found that being happy and/or satisfied with your life today is likely to benefit your health a few years in the future. After examining data collected in Australia in 2001 and 2004, Siahpush, found "very strong evidence that both happiness and life satisfaction have an effect on health," he wrote us.

"People who are happier and people who are more satisfied with their lives will be healthier in the future," Siahpush continued," and these results are independent of several factors that could affect health, such as physical activity, smoking status, alcohol consumption, age, gender, education, income, occupation and marital status."

Graphic: Jawahar Swaminathan, European Bioinformatics Institute.

Fibrinogen, a protein involved in blood clotting, can also be a predictor of cardiovascular trouble.

And these were not just peanut-sized benefits, Siahpush continued. "It is important to note that we found that the effects of happiness and life satisfaction are larger than the effects of smoking and exercise on health."

What is the mechanism?

It's easy to envision how health could promote happiness, but what could cause the opposite sequence? A study focused on correlation cannot pinpoint cause, and as Siahpush and colleagues conceded in the American Journal of Health Promotion, "Little work has been done to specify the mechanisms of the effect of happiness on health." One study, Siahpush pointed out, associated happiness among middle-aged people to improvements in cardiovascular signs and a reduction in cortisol, a stress hormone that contributes to type 2 diabetes, hypertension and autoimmune disease.

Happiness can also lead to a reduction in plasma fibrinogen, a predictor of coronary heart disease, Siahpush wrote us, adding that a positive affect (a sunny, optimistic personality) seems to improve thought processes and attention span, which help us overcome adversity and enhance physical health. "Positive affect also corrects or undoes the ill effects of negative emotions... and can help cardiovascular recovery after an [intense] negative emotion," Siahpush wrote.