The study, published in the American Journal of Epidemiology, included 2,873 healthy men and women between the ages of 50 and 74. Over the course of one day, six samples of their saliva were collected so that researchers could measure the cortisol levels. After taking each sample, participants recorded their current mood – the extent to which they felt “happy, excited or content.”
They found that men and women who reported happier moods had lower average cortisol levels over the course of the day – even when factors such as age, weight, smoking, and income were taken into account.
If happier people are healthier people, the more challenging and difficult question will continue to be: How do you become happier? Steptoe says: “People’s mood states are not just a matter of heredity, but depend on our social relationships and fulfillment in life. We need to help people recognize the things that make them feel good and truly satisfied with their lives, so that they spend more time doing these things.”