A happy outlook significantly reduces a person's risk of suffering a heart attack and cardiac death, researchers have found.
A team from John Hopkins University School of Medicine found that people with a cheery disposition are considerably less likely to suffer from a coronary event.
The study, led by Lisa Yanek and published in the American Journal of Cardiology, found that people who are born with cheerful personalities are more likely to take care of themselves and have more energy to do so.
The researchers found that people with higher levels of wellbeing still had risk factors for coronary diseases but got far fewer heart attacks.
Previous research had found that depressed and anxious people were much more likely to have heart attacks and die but this was the first study that looked at how cheerfulness reduced risk.
The team examined medical data of 1,483 siblings of people who had had coronary events before they had turned 60.
Researchers found that siblings of people who had early-onset coronary heart disease were twice as likely of developing it also, meaning a genetic predisposition to coronary problems.
Happier means healthier
Participants were asked to fill out wellbeing surveys which were scored on a scale between 0 and 110. Their cheerfulness, mood, level of concern about health and how relaxed they were was measured.
Over an average of 12 years, there were 208 coronary events. The scientists found that unhappy participants were three times more likely than happy respondents to have be victims.
Even high-risk subjects, based on age, smoking, high cholesterol, diabetes and high blood pressure, were half as likely to suffer a coronary event if they were happy.
The team repeated the study with 5,992 participants from the general population and found that cheerful people were 13% less likely to suffer.
Yanek said the protective effect of wellbeing was unclear but that the research had implications for the mind-body relationship.
She said: "If you look on the bright side of things, you are more likely to be protected from cardiac events.
"A happier temperament has an effect on disease and you may be healthier as a result."