Playing roulette with your body

They may look cool, but underneath their hearts are racing, adrenaline is rushing and hormone levels are all but overflowing.

Whether the stakes are low or high, the heart rate of the gambler increases by up to 29 beats a minute, and so much adrenaline is being produced that levels are still above what they should be hours after the last spin of the roulette wheel.

Also swishing about are testosterone and other hormones that help to give a gambler the buzz.

Natural opiates, too, are being churned out at every throw of the dice and turn of the card, and these are what help to get the gambler hooked.

Then there is a chemical called 3-methoxy-4 hydroxy-phenolglycol, which is thought to work on the mind to keep problem gamblers obsessed with betting.

The levels of one hormone, cortisol, in problem gamblers has been found to be as high as that caused by heavy exercise or by falling in love.

For years the only ill-effects of gambling were believed to be in the mind and on the bank balance, but there is increasing evidence that the health of the body is affected too.

"Apart from excessive moodiness and irritability, it is being shown that physiological effects include insomnia, high anxiety, stomach cramps, and nausea," says Dr Mark Griffiths, research co-ordinator in psychology at Nottingham Trent University and a leading expert on gambling .

With the latest relaxations in gambling controls, there is concern that many more people will gamble and that, as a result, there will be greater health problems, especially among the estimated one million-plus serial and pathological gamblers in Britain.

Exactly how many people gamble is not known, but it is estimated that 70 per cent of the adult population will have a flutter at some time, whether it's the lottery, fruit machine, bingo, football pools, or the casino - and that doesn't even count those who dabble in stocks and shares.

The reason why some gamblers become problem gamblers, while others do not, is no clearer than the reason why only some people who drink become alcoholics.

But there are clues. Researchers are increasingly finding that physiological changes occur in the bodies of gamblers that are not found in non-gamblers. Some scientists have even found physical differences in the brains of pathological gamblers.

In one area of the brain - the frontal cortex - they discovered features that are also seen in people suffering with obsessive-compulsive disorders and drug addiction.

Another link with obsessive compulsive disorder has been found in the elevated levels of 3-methoxy-4 hydroxy-phenolglycol in the spinal fluid of gamblers. This chemical is also present at higher rates in people who have impulsive tendencies.

There are other differences, too, in serial gamblers. Researchers have found that the heartbeat increases by between six and 29 beats a minute when they take part in their favourite game, compared with no rise at all in more moderate gamblers.

Adrenaline levels in the urine of gamblers after they have won are also higher than in non-gamblers.

The heartbeat rate goes up more when heavy gamblers are winning, suggesting that excitement may be the main motive for gambling. That theory is reinforced by the discovery of similar increases in hormone levels.

One group of researchers found that in blackjack players, both heartbeat and production of cortisol went up during the game.

Cortisol is a steroid hormone that is released in response to stress, and it may be the root cause of gambling addiction. The stresses that can stimulate the release of cortisol include drastic changes in temperature, heavy exercising or falling in love

Scientists have also found that naturally occurring opiates are at increased levels in gamblers, adding weight to the idea that problem gambling is a form of addiction. The more the gambler gambles, the greater the production of these natural opiates or endorphins.

Although there are a number of treatment options for problem gambling, it is often difficult to cure. One of the most widely used treatments is group therapy, but there is also hypnotherapy, and more than a dozen others.

One of the least popular is aversion theory, when an electric shock is associated with gambling. In another therapy - paradoxical intention - the therapist tells the client to bet according to a strict schedule, whether the gambler wants to or not. Many say it's highly effective... though don't bet on it.