Willy Trolove: Laugh and your vascular system will say thank you

According to the latest research presented last month in Orlando, Florida, at a meeting of the American College of Cardiology (motto: we state the bleedingly obvious), laughter is good for you.

Next month the college is expected to publish research indicating that crossing the road is dangerous and, more controversially, that fat people eat too much.

After that, they will go on to prove that gravity works in a downwards direction, and that the sun rises every day (even when it's cloudy).

Seriously, though, according to the good doctors, laughter makes our blood vessels work more effectively.

Laughing can improve our fitness just as much as some forms of mild exercise, such as, presumably, walking, yoga or trying to erect a sun-lounger.

"We don't recommend that you laugh and not exercise," said Dr Michael Miller, of the University of Maryland, "but we do recommend that you try to laugh on a regular basis ... 15 minutes of daily laughter is probably good for the vascular system."

And so, ladies and gentlemen, your vascular system needs you. Get laughing.

The problem is that you can't really plan laughter. You can't sit down at the end of the day and say, "Right, I'm going to have my daily laugh now and start guffawing uncontrollably for the next 15 minutes".

Unless, of course, you happen to be the Prime Minister, and you can't believe that you are still way ahead in the polls despite everything that John Tamihere said.

No. Laughter requires spontaneity, surprise and, just occasionally, exploding trousers. Unfortunately, none of these things can be predicted with any kind of reliability.

But humans are a uniquely ingenious species (we know this because even though a number of other mammals have just as much hair as we do, none of them has, as yet, invented the hairdryer) and we have used our unique ingenuity to develop ways of providing laughter on demand. For example, we have invented jokes.

Jokes have become such an integral part of our lives that we have developed the internet. This is so that we can share jokes with people we met briefly in a pub once, and who we feel obliged to stay in contact with on the outside chance that, thanks to some extraordinary set of circumstances, they might one day be able to get us some Lions tickets.

The only truly funny jokes are smutty, sexist, xenophobic or involve your boss caught in a compromising situation - usually with Warren from marketing.

Truly funny jokes are now banned in the workplace and, more recently, in pubs. Drive past a pub late at night and you will see groups of pub-goers huddled together outside. These people are telling jokes to each other about Irishmen, blondes and Warren, with his uncommon fondness for tanning products.

Slapstick humour is another kind of laughter on demand. This is particularly effective at work. It can involve, say, deliberately answering the wrong telephone, making an artillery noise whenever a co-worker says "fire away", and pretending that you are a pirate during your performance review.

Sight gags are just as amusing. Try doing ridiculous things with your hands or pulling an absurd face like, for example, this (see), or this (oh yes, that's a good one), or even this (ha ha ha). Obviously, sight gags don't work very well in the newspaper.

Various substances can also help make us laugh. There is alcohol, which is now frowned upon because it allows people to enjoy their lives, and laughing gas, now available only from dentists.

There are also American sitcoms, although, for some reason, the laughter generated by these is confined to the live studio audience.

The research presented by the American College of Cardiology does, however, overlook an important point. Laughter may be good for us, but only to an extent.

You see, the phrase "I nearly died laughing" is not so much a sign of a good time but more a warning of what can happen when laughter gets out of hand.

According to the Book of Lists, there are at least nine documented cases of people who have laughed themselves to death.

My favourite is an unfortunate (or fortunate, depending on how you look at it) English bricklayer called Alex Mitchell. Some time in 1975 Mr and Mrs Mitchell were watching the TV comedy The Goodies.

In the middle of the show Mr Mitchell was seized by uncontrollable laughter. After half an hour of unrestrained mirth, he suffered a heart attack and died.

His wife wrote to The Goodies thanking them for making her husband's last moments so happy.

Death is usually a serious affair. But when someone dies laughing you have to say that it is, if nothing else, a funny way to go.