The joy you experience watching your son getting married, becoming a grandparent or meeting an old friend after years apart can cause as much damage to your heart as severe stress, anger or grief, a new study claims.
While three-quarters of cases of takotsubo cardiomyopathy - which can be fatal, although in most cases is temporary - researchers at the University Hospital Zurich claim that one in 20 cases was caused by joy.
A study of 1,750 patients, published in the European Heart Journal, found heart problems were brought on by happy events such as a birthday party, a son's wedding, meeting an old friend, becoming a grandmother, a favourite rugby team winning a game or winning a jackpot at the casino.
Ironically, patients receiving the all-clear from another condition were also liable to suffer from this condition.
Dr Jelena Ghadri, one of the researchers, said: "We have shown that the triggers for takotsubo syndrome can be more varied than previously thought.
"A takotsubo syndrome patient is no longer the classic 'broken-hearted' patient, and the disease can be preceded by positive emotions too.
"Clinicians should be aware of this and also consider that patients who arrive in the emergency department with signs of heart attacks, such as chest pain and breathlessness, but after a happy event or emotion, could be suffering from takotsubo syndrome just as much as a similar patient presenting after a negative emotional event."