Lead author, Andrew Steptoe, Ph.D., said:
"We had expected that we might see a link between how happy people felt over the day and their future mortality, but we were struck by how strong the effect was."
Steptoe and team asked 3,800 individuals aged between 52 and 79 to write down how they felt at four different times during a single day. Unlike prior studies that focused on lifespan and happiness, this one did not rely on how well participants could remember a certain period in their lives, which are often inaccurate. In this study, they were writing down how they felt at that moment.
The participants were divided into three groups:
- The happiest group
- The middle group
- The least happy group
Five years later, the authors found that:
- 3.6% of those in the happiest group had died
- 4.6% of those in the middle group had died
- 7.3% of those in the least happy group had died
A smiling 95-year old Chilean man from Pchilemu
The authors explained that their findings indicate that experienced levels of happiness ("personal affects") are linked to survival chances that are not caused by variables such as health status, etc.
The authors wrote in an abstract in the journal:
"Momentary PA (personal affect) 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."