Laughter the best medicine? Actually, not always - too much may even harm you

Chuckling too hard can even lead to heart ruptures, torn gullets and incontinence

Plenty to laugh about: David Warner of Australia shares a laugh with his team during a nets session in Perth (Mark Kolbe/Getty Images)

Having a fit of the giggles might seem harmless and, if anything, good for you. Yet contrary to the popular belief that it is the best medicine, research has revealed that too much laughter might actually be harmful for you.

In a study that looked at all the reported benefits and damage of laughter from the last 67 years, researchers from the universities of Oxford and Birmingham found that chuckling too hard can in some cases lead to heart ruptures, torn gullets and incontinence.

According to the report, taking a sharp intake of breath as you laugh also presents dangers, as not only can it lead to foreign objects being lodged in your throat, but also provoke an asthmatic attack.

According to the research, having a heart condition can also put you at risk of fatal chuckling, with one woman with racing heart syndrome collapsing and dying after laughing too much.

However, the study also found that the benefits of laughter are numerous. In one test, clowns sent into a hospital to entertain the patients were shown to improve lung function among those with chronic obstructive pulmonary disease.

What's more, thirty-six per cent of women undergoing IVF treatment became pregnant after being entertained by the troupe of clowns, compared to only 20 per cent of IVF patients in a control group. And according to the study, experiencing a bout of "genuine laughter" for a day can also burn up to 2000 calories.

The researchers say that their findings demonstrate that laughter isn't always beneficial, although they have stressed that in most cases it only ever carries a 'low risk of harm and may be beneficial'.

As to the effect different types of humour have, the researchers have said that there is still work to be done. "It remains to be seen whether sick jokes make you ill, dry wit causes dehydration or jokes in bad taste cause dysgeusia (distortion of sense of taste)," they said.

The findings were reported in the BMJ Christmas edition.