(Medical Xpress) -- Dont Worry. Be Happy. The words from this famous song may have more meaning than originally intended according to a new study published in the journal Proceedings of the National Academy of Sciences. According to study results, people who report feeling happy on a daily basis are 35 percent less likely to die compared to their unhappy counterparts.

Previous studies on happiness and longevity have looked at how people felt in the past. These recollections of feelings are not always accurate. Not everyone can remember exactly how they felt last Tuesday, so the information is a bit faulty.

For this study, researchers led by Professor of Psychology at the University College London, looked at 3,800 participants between the ages of 52 and 79. They were asked to record their levels of happiness, anxiety and a variety of other emotions at four specific points throughout one particular day.

Based on answers, the researchers divided the participants into three groups based on their level of happiness and positive feelings. Each group was comparable in ethnic makeup, employment status, overall health and education but varied in terms of age, wealth and whether or not they smoked.

After a period of five years, the researchers discovered that within in the groups, seven percent of the least happy group had passed away compared to only four percent in the happiest of the three groups. The middle group was at five percent.

Researchers then looked at each group again and controlled for age, chronic diseases, exercise, alcohol consumption, depression and socioeconomic factors. With these factors taken into consideration, they discovered that 35 percent of the happiest group was less likely to have died and the middle group of happiness was 20 percent less likely.

Researchers say that positive emotions affect regions of the brain that also work in blood vessel function and inflammation. The hormone cortisol is also affected by changes in emotion and could play a role.

While this study does not directly prove that happiness affects lifespan, it does suggest that physicians should pay close attention to the emotional state of their older patients. Steptoe believes that these findings provide a reason to target the positive well-being over older patients to improve health.

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More information: Positive affect measured using ecological momentary assessment and survival in older men and women, PNAS, Published online before print October 31, 2011, Positive affect measured using ecological momentary assessment and survival in older men and women,, Published online before print October 31, 2011, doi: 10.1073/pnas.1110892108 Abstract

Links between positive affect (PA) and health have predominantly been investigated by using measures of recollected emotional states. Ecological momentary assessment is regarded as a more precise measure of experienced well-being. We analyzed data from the English Longitudinal Study of Aging, a representative cohort of older men and women living in England. PA was assessed by aggregating momentary assessments over a single day in 3,853 individuals aged 52 to 79 y who were followed up for an average of 5 y. Respondents in the lowest third of PA had a death rate of 7.3%, compared with 4.6% in the medium-PA group and 3.6% in the high-PA group. Cox proportional-hazards regression showed a hazard ratio of 0.498 (95% confidence interval, 0.3450.721) in the high-PA compared with the low-PA group, adjusted for age and sex. This was attenuated to 0.646 (95% confidence interval, 0.4360.958) after controlling for demographic factors, negative affect, depressed mood, health indicators, and health behaviors. Negative affect and depressed mood were not related to survival after adjustment for covariates. These findings indicate that experienced PA, even over a single day, has a graded relationship with survival that is not caused by baseline health status or other covariates. Momentary PA may be causally related to survival, or may be a marker of underlying biological, behavioral, or temperamental factors, although reverse causality cannot be conclusively ruled out. The results endorse the value of assessing experienced affect, and the importance of evaluating interventions that promote happiness in older populations.

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