Those who 'always look on the bright side' are more likely to live longer and make it past 90, a new large-scale study finds.
In fact, looking at the glass half full could even be as good for you as exercise, Lead author Hayami Koga, a PhD candidate at the Harvard T.H. Chan School of Public Health, believes.
Researchers also found the benefits of optimism applied across racial and ethnic groups, and the contribution of lifestyle factors to longer lifespan and the likelihood of exceptional longevity (living past a certain age), while evident, was 'modest'.
The new findings – published in the Journal of American Geriatrics Society – are based on 159,255 women in the US who were tracked for up to 26 years.
They were assessed using the 'Life Orientation Test' questionnaire, one of the most commonly used measures of optimism in research and practice.
Other factors like education, marital status, income and chronic conditions were taken into account.
Those who ranked in the top 25% for optimism lived an average of 5.4% longer than participants in the lowest quarter.
"Although optimism itself may be patterned by social structural factors," explains Koga, "our findings suggest that the benefits of optimism for longevity may hold across racial and ethnic groups.
"Optimism may be an important target of intervention for longevity across diverse groups."
While optimism – the tendency to be hopeful and to think of the best rather than the worst – is partly in the genes, it has also been proved to be inspired by writing exercises and cognitive behavioural strategies.
"This work, in conjunction with findings linking optimism to a range of outcomes including physical health, suggest optimism may be a novel target for intervention to improve health," Koga adds.
As well as being associated with improved health outcomes including 'exceptional longevity', research has also suggested those who are optimistic take more proactive approaches to promoting their health, and are more likely to engage in healthy behaviours like increased physical activity, healthier diet and not smoking.
"This evidence suggests such behaviours may mediate the relationship between optimism and longevity," says Koga.
She adds, "Of note, exercise has been widely recognised as an important factor for health and studies have shown that regular exercise adds 0.4 to 4.2 years of life when adjusting for confounding risk factors.
"Thus, our findings suggest the impact of optimism may be comparable to that of exercise."
Psychological stress and distress can also trigger a host of physiological changes that are bad for health, she explains. These can include activation of the immune and autonomic nervous system, changes in brain chemicals, blood clot and oxidative stress
"Positive psychological factors may buffer psychological stress as well as the physiologic reactions," says Koga.
"In addition optimists appear to have greater social support, use problem-solving and planning strategies to minimise health risks and are better able to regulate emotions and behaviour."
In summary, she says, "We found that higher levels of optimism were associated with longer lifespan and greater likelihood of achieving exceptional longevity across racial and ethnic groups, suggesting the health benefits of optimism may hold across these groups.
"Thus, while some evidence suggests optimism itself is patterned by some social structural factors, meaningful associations between optimism and health remain even after robust adjustment for these factors and when examined separately across race and ethnic groups.
"The contribution of lifestyle to these associations was evident albeit modest. As prior work has demonstrated that optimism is modifiable, it may be a novel target for interventions that aim to extend lifespan across diverse racial and ethnic groups."
So, rather than longevity for the sake of longevity, it seems seeing the glass have full can not only make you live longer, but make you healthier for a better quality of life too.
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Additional reporting SWNS.