Always look on the bright side of life, so the song goes. And there may be some pretty solid reasons to do so, it has emerged.

For science has proven that the glass half full side of society – optimists – do live longer. According to major new research spanning 30-years, scientists found a clear link between optimism and prolonged life.

The findings show that people with greater optimism are more likely to live longer and to achieve “exceptional longevity” – living to the age of 85 or even older.

Optimism was defined as a general expectation that good things will happen, or believing that the future will be favourable because we can control important outcomes. 

Previous studies have identified many risk factors that increase the likelihood of diseases and premature death, but much less is known about positive factors that can promote healthy ageing.

The latest American study was based on 69,744 women and 1,429 men. 

They completed surveys to assess their level of optimism, as well as their overall health and wellbeing habits, such as diet, smoking and alcohol consumption. 
The women were followed for 10 years, while the men for 30 years. When participants were compared based on their initial levels of optimism, the researchers found that the most optimistic men and women had, on average, an 11 to 15 per cent longer lifespan, and had 50 to 70 per cent greater odds of reaching 85 years old compared to the least optimistic groups. 

The results were maintained after accounting for age, demographic factors such as educational attainment, chronic diseases, depression and also health factors such as alcohol consumption, exercise, diet and primary care visits.

Study corresponding author Dr Lewina Lee, Assistant Professor of psychiatry at  Boston University School of Medicine, said: “While research has identified many risk factors for diseases and premature death, we know relatively less about positive psycho-social factors that can promote healthy ageing.

“This study has strong public health relevance because it suggests that optimism is one such psycho-social asset that has the potential to extend the human lifespan. 
“Interestingly, optimism may be modifiable using relatively simple techniques or therapies.”

But it remains unclear how exactly optimism helps people attain longer life. Study senior author Professor Laura Kubzansky, of the Harvard TH Chan School of Public Health, said: “Other research suggests that more optimistic people may be able to regulate emotions and behaviour as well as bounce back from stressors and difficulties more effectively.”

The findings were published in the journal Proceedings of the National Academy of Sciences.