In the research, more than 270 healthy men ages 19 to 64 who were not taking blood pressure medication wore automatic blood pressure cuffs. They were first asked to lie down face up and later were told to turn over on their stomachs.

In almost all the men, their overall blood pressure dropped significantly when they were face down. And 25 of the men experienced an even more dramatic decrease of more than 15 points when they just turned over onto their stomachs.

In addition, systolic blood pressure, which is the force blood exerts on the artery walls when the heart beats, fell by as much as 15 mmHg in response to moving into the prone position, compared with the supine position, reports Patient Health International.

Those who curl up in the foetus position are described as tough on the outside but sensitive at heart. They may be shy when they first meet somebody, but soon relax. This is the most common sleeping position, adopted by 41% of the 1,000 people who took part in the survey. More than twice as many women as men tend to adopt this position.

Log

Lying on your side with both arms down by your side. These sleepers are easy going, social people who like being part of the in-crowd, and who are trusting of strangers. However, they may be gullible.

Yearner

People who sleep on their side with both arms out in front are said to have an open nature, but can be suspicious, cynical. They are slow to make up their minds, but once they have taken a decision, they are unlikely ever to change it. 

Soldier

Lying on your back with both arms pinned to your sides. People who sleep in this position are generally quiet and reserved. They don’t like a fuss, but set themselves and others high standards.

Freefall

Lying on your front with your hands around the pillow, and your head turned to one side. Often gregarious and brash people, but can be nervy and thin-skinned underneath, and don’t like criticism, or extreme situations.

Starfish

Lying on your back with both arms up around the pillow. These sleepers make good friends because they are always ready to listen to others, and offer help when needed. They generally don’t like to be the centre of attention.

The remainder of those in the poll said the position they fell asleep varied or did not know.

Professor Idzikowski also examined the effect of various sleeping positions on health. He concluded that the freefall position was good for digestion, while the starfish and soldier positions were more likely to lead to snoring and a bad night’s sleep.

Professor Idzikowski said “Lying down flat means that stomach contents can more readily be worked back up into the mouth, while those who lie on their back may end up snoring and breathing less well during the night. “Both these postures may not necessarily awaken the sleeper but could cause a less refreshing night’s sleep.”

The research also found that most people are unlikely to change their sleeping position. Just 5% said they sleep in a different position every night.