Women often fail to realise they have had a heart attack because they can cope better with the pain, researchers have suggested.
Experts are increasingly concerned that many heart attacks among women are missed.
Women in Britain are 50 percent more likely than men to have a heart attack initially misdiagnosed.
The research by scientists in Norway suggests that although, in general, men can cope with more pain than women, women seem to be more able to cope with the specific pain of a heart attack.
This may mean they are more likely to suffer a ‘silent’ heart attack – in which a patient does not realise what has happened.
Dr Andrea Ohrn, of the University of Tromso in Norway, said, “It is unknown why some people experience heart attacks without symptoms. One possible explanation for the absence of chest pain is high pain tolerance.”
The researchers studied the pain tolerance of 4,849 adults by immersing their hands in cold water at 3C for up to two minutes.
The team also used ECG scanners to see whether a patient had suffered a heart attack in the past.
They found those who could endure the pain the longest were most likely to have suffered a ‘silent’ heart attack in the past, for which they had never been diagnosed.
And this link between pain threshold and silent heart attack was stronger among women.
Overall, fewer women had suffered heart attacks than men – 7 percent compared with 19 percent – but a larger proportion of heart attacks were silent in women than in men – 75 percent compared with 58 percent.
Women tended to pull their hands out of the cold water quicker than men, but the researchers, whose results were published last night in the Journal of the American Heart Association, found that the statistical link between silent heart attack and pain tolerance was stronger in women.
This may be because women are better able to cope with the specific pain of a heart attack.
Experts also think the symptoms of heart attacks are different among women and men, which could also explain why they are less likely to notice them.
Dr Ohrn said, “Asking patients about their pain sensitivity might provide a clearer picture. Absence of chest pain should not lower alertness of doctors towards heart disease.”
Some 69,000 women have a heart attack in the UK every year, compared with 119,000 men. But women are more likely to die as a result of the attack.
An initial misdiagnosis can be fatal, driving up the chance of dying within a month by 70 percent.
Nearly half of the salvageable heart muscle is lost in the first hour of the attack starting. Yet only one in four attack victims get treated within this short window.
Many think a heart attack strikes suddenly, with victims clutching their chest and keeling over.
Instead, it happens gradually, with people typically complaining of nausea and an aching chest, jaw or arms.
Dr Mike Knapton, of the British Heart Foundation, said, “Silent heart attack is a major problem in the UK. It is worryingly common for patients to visit their GP having already had a heart attack but they are completely unaware of it.”
He added, “We know that women often don’t realise they can be at risk. This makes them more likely to ignore the symptoms and delay getting help.”