"When you're chewing on life's gristle, don't grumble, give a whistle", sang Monty Python's Eric Idle in the iconic track Always Look on the Bright Side of Life, and it turns out this might be more lifestyle advice than just a jolly jingle.
New research claims that keeping an optimistic outlook on life could give you a better chance of living longer, and - more than this - of reaching the age of 85 or older.
The study - published in the Proceedings of the National Academy of Sciences - adds weight to the argument that optimists have healthier lives in general, as previous research has found that those with a glass-half-full disposition have a lower risk of heart disease and early death.
The team analysed two long-term research projects which were carried out some years ago. The first followed a group of female nurses, with an average age of 70, from 2004 to 2014, monitoring their optimism. The second followed a group of men with an average age of 62, from 1986 to 2016.
They scored the 70,000 in terms of their optimism, splitting them into four equally sized groups. They compared the lifespan of the most optimistic group with that of the least, considering factors such as depression, education, sex, race, education and health conditions.
They found that the most optimistic group had a lifespan almost 15% longer than the least optimistic group.
The results were similar for the male group, with the research team finding that the most optimistic group had a lifespan almost 11% longer than the least.
The study also suggested that more optimistic people might lead healthier lives, so the research team looked at extra lifestyle factors such as diet, exercise, alcohol intake and smoking habits.
They then found that the more optimistic group of women had a lifespan 9% longer than the least optimistic group, and the men had a lifespan 10% longer than their least optimistic counterparts.
Even more compelling, however, was the suggestion that being optimistic could lead to "exceptional longevity", as the most optimistic group of women had a 20% higher chance of reaching the age of 85 and older.
That said, the majority of the participants in this study were white and mostly came from higher socioeconomic status, so it is uncertain how this would translate into other groups.
"A lot of evidence suggests that exceptional longevity is usually accompanied by a longer span of good health and living without disability, so our findings raise an exciting possibility that we may be able to promote healthy and resilient ageing by cultivating psychosocial assets such as optimism," said Lewina Lee, the lead author of the study at Boston University School of Medicine, as quoted in The Guardian.
She added that the team are unsure of what is behind the link between optimism and longevity, saying: "In our study, healthier behaviours, fewer depressive symptoms, and more social ties only partially accounted for the association from optimism to exceptional longevity,"
