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Happy and healthy: the more moments of happiness you experience in life, the healthier you’ll be

20 February 2006

Public health scientists at UCL have found that a happy state of mind can lead to a healthier heart and lower levels of stress-inducing chemicals. The research published online in Proceedings of the National Academy of Sciences (PNAS) on 18th April says that people who have more moments of happiness over a day produce less harmful chemicals such as cortisol and so are likely to be healthier long-term and less likely to suffer from heart disease.

The research, part of the Whitehall II study, shows the health effects of happiness by testing middle-aged Londoners - 116 men and 100 women - in a number of different situations including at work, leisure and in a laboratory. The tests at work and during leisure periods were performed regularly during the day and the subjects were asked whether or not they were happy at these moments. Over a full day, an average of happy moments was taken. The subjects ranged from those who never felt happy to those who felt occasional happiness and finally, those who felt happy most of the time.

Most people felt happiest during their leisure hours than at work. However, those who were happiest overall experienced lower levels of the stress hormone, salivary cortisol, during a working day than those were rated themselves as happy less frequently. The results were adjusted for gender, age, employment status, body mass index (BMI), smoking, and psychological distress. Interestingly, in men, happiness also had an impact on heart-rate – men who were happiest had a lower heart rate (between 68 and 70 bpm) than those who had a low rate of happiness (these men clocked in at over 76 bpm). The same was not true for women. The main chemical difference in both men and women who were generally unhappy and those who were more often happy was the amount of the chemical plasma fibrinogen found in the blood stream – a major predictor of cardiovascular disease risk.

Professor Andrew Steptoe led the study with Professor Sir Michael Marmot and Professor Jane Wardle from the psychobiology group at UCL’s Department of Epidemiology. Professor Steptoe said: “It has been suspected for the last few years that happier people may be healthier both mentally and physically than less happy people. What this study shows is that there are plausible biological pathways linking happiness with health. Cortisol has effects on a number of bodily systems related to health, so the lower levels that we have recorded during people’s everyday lives are potentially important. Fibrinogen is a substance that is directly related to risk of coronary heart disease, and the finding that happier individuals have lower fibrinogen responses to stress suggest that this could be a mediating mechanism.

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.”

The study is part of the major Whitehall II psychobiology study which involves 10,308, London-based civil servants recruited between 1985 and 1988 when 35-55 years old to investigate the risk factors for coronary heart disease. It has been funded by the Medical Research Council and the British Heart Foundation.

Notes for Editors

1. The paper will appear online on Proceedings of the National Academy of Sciences (PNAS) on 18th April.
2. Please contact Alex Brew at UCL’s press office on 020 7679 9726 or a.brew@ucl.ac.uk