Smiley, happy people have healthy hearts

Happiness is good for the heart, thinning the blood, reducing its stickiness, and cutting the level of the stress hormone cortisol, according to psychologists from University College London.

The more happiness people experience the better their health is likely to be, they say.

While the adverse physical effects of depression and anxiety are well known, the biological impact of a good mood has not been demonstrated before, they claim.

The finding, published online in Proceedings of the National Academy of Sciences, comes as separate research shows that the risk of heart disease as an adult is increased by childhood infections such as colds and flu.

Researchers found the flexibility of the arteries in 600 children was reduced during an infection and in some cases did not recover after the infection was over.

Artery flexibility is a key risk factor for heart disease and the researchers suggest in the journal Circulation that there could be a link between this and infections suffered in childhood.

In the study examining the impact of happiness on health, 116 middle-aged men and 100 women from London were monitored at work and leisure and tested in a laboratory.

They gave blood and saliva samples and rated their happiness at different times. Some of the participants never felt happy while others felt happy all the time. Most were happiest during their leisure hours.

The happier people had lower levels of fibrinogen, a clotting factor in the blood which increases the risk of heart attack.

They also had lower levels of cortisol, the stress hormone, even when subjected to stressful tests, indicating that they coped better with adverse events.

The results showed for the first time that there are "plausible biological pathways" linking happiness with health, the authors said.

Andrew Steptoe, professor of psychology, who led the study, said: "What we find particularly interesting is that the associations between happiness and biological responses were independent of psychological distress.

"We already know that depression and anxiety are related to increased physical health risk. This study raises the intriguing possibility that the effect of happiness may be somewhat separate."

Jane Wardle, professor of psychology and an author of the study, said: "If you think of psychological well-being on a scale from happy at the top through neutral to depressed at the bottom, most research has looked at the bottom part of this distribution.

"What we have found, by looking at the top part, is that there could be a whole other side involving happiness which affects biological factors."

- INDEPENDENT