Your body language can often reveal what you’re thinking and even personality traits. This too applies to your body language when you’re sleeping.

The U.K.’s Daily Telegraph recently reported that Robert Phillips, a body language expert, studied four of the most popular positions and revealed what they could say about a person. The four positions he studied were fetal, log, yearner and freefall.

Phillips says fetal, the most popular position, involves sleeping on one’s side with the knees curled upward and neck bent slightly downward. This position, the Telegraph reports, brings a person back to their comfort zone. From Phillips’ observations, those who sleep this way are considerate and orderly, but also have the potentially to be over-thinkers and worriers.

Sleep Positions Might Indicate Personality Traits

The fetal position. (Photo: Shutterstock.com)

Log sleepers, those who lie in a straight position with their arms down, could indicate a more strict, stubborn personality. Whereas those favoring the yearner’s position, sleeping on one’s side with arms stretch outward sideways, are said to be go-getters who can also be critical of themselves.

Sleep Positions Might Indicate Personality Traits

Arms reaching outward in this way indicate what’s called the “yearners” position. (Photo: Shutterstock.com)

Those in a freefall position, lying on one’s stomach with arms stretched out, might indicate a personality that feels a lack of control over their life. It is also said to be one of the more unfavorable and uncomfortable positions for adults.

Sleep Positions Might Indicate Personality Traits

The freefall position looks similar to skydiving. (Photo: Shutterstock.com)

The Telegraph reports Phillips conducting this research for Premier Inn, a U.K. hotel chain. A spokesperson for the chain is reported as saying that while some people read horoscopes, the hotel wanted to show guests how their night sleep might indicate how they could face the day.

“We have worked with Robert to develop ‘sleep-o-scopes’ and were shocked that the research revealed just how stressed we are as a nation,” spokeswoman Claire Haigh said.

Watch this recent CBS video with another body language expert discussing the different positions:

This report adds two categories to the list in addition to what Phillips spoke of: soldier and starfish. Soldier is lying on one’s back with arms to one’s side. Starfish is similar except the arms bend upward toward the head. Those sleeping in starfish were reported to be good friends.

Sleep Positions Might Indicate Personality Traits

Arms above the head like this indicate the starfish position. (Photo: Shutterstock.com.)

CBS’ report shows some differences in the definitions of what constitutes the sleep positions, compared to Phillips observations, but the sentiments of what each mean are relatively similar.