For those suffering from disorders such as sleep apnoea and snoring, certain positions were more likely to worsen the problem, but he was cynical about any link between sleeping positions and personality.
Sleep physiologist Kareen Mitchell, from NZ respiratory and Sleep Institute, was also unsure about the findings.
"As far as I know it's more a preference (position) really."
Getting a good night's sleep was more about "sleep hygiene", including habits such as going to sleep at the same time each night and not drinking coffee or exercising close to bedtime, she said.
UK body language expert Robert Phipps, who conducted the research for the hotel chain Premier Inn, admitted it wasn't meant to be taken "absolutely seriously".
The body language we used when sleeping could tell us a lot about how we're feeling at the time, and could affect the day ahead from the moment we wake up, he said.
Foetal sleeping was the most common, and people who slept like that were returning to their comfort zone to de-stress themselves from the day's activities, Mr Phipps told the Daily Mail.
The higher the knees and lower the head, the more internal comfort sleepers gave themselves.
"Foetal sleepers are conscientious, ordered and like things in their place, but they can over-think things and worry unnecessarily," he said.
The Log was the second most common sleep position - fully extended with head, neck, arms, legs and body stretched in a straight line.
"The longer you sleep like this the more rigid your thinking, you can become inflexible making things harder for yourself. Loggers are set in their ways and can be stubborn, liking things done their way, which can make them come across as bossy or even aloof," Mr Phipps said.
Third most common was the yearner, with arms outstretched as though chasing dreams - or it could mean the sleeper was being chased.
"You feel you want more from life and are willing to go out there and get it with both hands, ready to capture every new and exciting challenge that comes your way," Mr Phipps said.
Yearners were their own worst critics, always expecting great results in everything they did, which could mean giving up to quickly with things that didn't go their way right from the start.
Freefalling was the least popular and least comfortable of the four sleep positions with the whole body outstretched flat on the stomach, arms at right angles, hands gripping the pillow as though holding on for dear life.
"Freefallers tend to feel like life happens around them and they are just hanging on for the ride, which can make them feel like they're not in control of what happens," Mr Phipps said.
They could wake up feeling like they still had things left over from the previous day which could make them feel over-anxious about getting things done the next day.
