NEW YORK • An increasing number of recent long-term studies have linked greater optimism to a lower risk of developing cardiovascular disease and other chronic ailments and to fostering "exceptional longevity", a category one team of researchers used for people who live to the age of 85 and beyond.
Admittedly, the relationship between optimism and better health and a longer life is only a correlation that does not prove cause and effect.
But there is now biological evidence to suggest that optimism can have a direct effect on health, which should encourage both the medical profession and individuals to do more to foster optimism as a potential health benefit.
Dr Alan Rozanski, one of the field's primary researchers, says: "It's never too early and it's never too late to foster optimism. From teenagers to people in their 90s, all have better outcomes if they're optimistic."
Dr Rozanski is a cardiologist at Mount Sinai St Luke's Hospital in New York who became interested in optimism while working in a cardiac rehabilitation programme early in his career.
He explained: "Many heart-attack patients who had long been sedentary would come into the gym and say, 'I can't do that!' But I would put them on the treadmill, start off slowly and gradually build them up. Their attitude improved; they became more confident."
In an analysis of 15 studies involving 229,391 participants published last September in Jama Network Open, Dr Rozanski and his colleagues found that people who ranked high in optimism were much less likely to have a heart attack or other cardiovascular event.
They also had a lower mortality rate from any cause than pessimistic participants in the studies.
Dr Rozanski described the data as very consistent, adding: "In every case, there was a strong relationship between optimism and a lower risk of disease. Optimists tend to take better care of their health. They're more likely to exercise and eat better and are less likely to smoke.
"There's also a biological effect... Pessimism increases inflammation in the body and fosters metabolic abnormalities like diabetes. Pessimism is also on the way to depression, which the American Heart Association considers a risk factor for cardiovascular disease."
Another researcher, Dr Julia Boehm, a psychologist at Chapman University in California, said: "Optimism promotes problem-solving. It helps people deal with challenges and obstacles in more effective ways. Optimists tend to pursue strategies that make a rosy future a reality. Their hearts are not constantly pounding.
"Pessimists tend to not be open to the possibility of favourable outcomes and the fight-or-flight response they experience amps up bodily systems that, over a long period of time, wear the body down."
Dr Boehm and her colleagues examined the association of optimism with three health behaviours - physical activity, diet and cigarette smoking - and found that more optimistic individuals were more likely to engage in healthier behaviours.
Their findings were published in Circulation Research in 2018.
Dr Rozanski cited the tenets of cognitive behavioural therapy as a way to foster greater optimism in chronic pessimists, which can help people develop better coping skills and counter negative thoughts.
"Our thinking is habitual, not conscious, so the first step is to learn to catch yourself when thinking negatively and make a commitment to change how you look at things," he advised.
"Recognise that the way you're thinking is not necessarily the only way to think about a situation. Just that thought alone can decrease the toxic effect of negativity.
"Step two is to substitute a better thought that is credible."