Laugh off stress the healthy way

Laughter is a great way to relax and release tension, which would suggest that a lively sense of humour can boost your cardiovascular health.

To test this hypothesis and investigate how laughter might protect arterial linings from the damaging effects of stress, cardiologist Michael Miller and his team asked healthy volunteers to watch comedy movies and studied the effects.

They found that laughter relaxed their subjects' blood vessels and boosted blood flow by almost 25 per cent — equivalent to the increases seen with light exercise or cholesterol-lowering drugs. Conversely, when the volunteers watched a tense dramatic film, their blood flow was reduced by more than a third — an effect similar to that caused by dwelling on bad memories or doing difficult mental calculations.

The saying "laugh and the world laughs with you" is not just a cute catch phrase. When researchers scanned volunteers' brains while playing tapes of sounds that ranged from people laughing and whooping with triumph to ones of then screaming and distressed, the positive sounds created much stronger responses.

The area of the brain that responds to triumphant sounds or laughter was the same as the one involved in smiling, which suggests that the brain actually primes us to respond to other people's smiles by smiling back.

This is also, of course, why some sitcoms include a laugh track at the end of gags — producers hope it will prompt a studio audience or viewers at home to laugh along too.

• For those who want to combine getting in shape with having fun, there is an international laughter movement that runs "laughter yoga" classes.
• This gives you a chance to get together with other people and laugh.
• It's an excellent aerobic workout, combining the physiological benefits of laughter with yogic breathing, which brings more oxygen to the body and brain.
• Laughter produces endorphins, making you feel good, reducing tension and relaxing your body.