Statistics show that men are up to eight times more likely than women to snore.

They are also more likely to suffer from sleep apnoea/hypopnoea syndrome (SAHS), a condition in which people stop breathing for several seconds while asleep.

Researchers at Western General hospital in Edinburgh, writing in the medical journal Thorax, believe the reason is a difference in the bulk of neck muscle.

Dr Adam Whittle, one of the research team, said: "What we found was that there are some small differences in the way the fat is distributed between the men and the women.

"But the big difference is likely to be in muscle bulk which could become a problem when people go to sleep."

Being overweight and having a thick neck are known risk factors for snoring and SAHS.

Dr Whittle and his team were puzzled why women, who have higher rates of obesity and greater overall body fat, did not snore as much as men.

Soft tissue distribution

The researchers assessed the soft tissue distribution, including fat, in the necks of 10 men and 10 women of average weight.

Even though the amount of fatty tissue in the neck was disproportionately high in men compared with the rest of their body, the overall amount of fat was more or less the same in both sexes.

However, the soft palate and the tongue contained more fatty tissue than the same areas in women, and the total amount of soft tissue in the neck was a third greater in men, most of which was accounted for by muscle bulk.

Snoring is caused by the vibration in an airway that is almost collapsed.

During the day the extra muscle bulk keeps the airways open but at night it could have the opposite effect.

Dr Whittle said: "When you go to sleep, the muscles relax so men may collapse their airways because of the extra muscle bulk around it."