“Many people fall asleep in a side-laying foetal position because it offers them a sense of safety as they doze off,” says mattress designer Susanne Flother. According to a 2013 survey it happens to be the most common sleeping position.
“Those who favour the side-lying foetal position tend to be sensitive, but may project a tough exterior,” says Professor Chris Idzikowski, who directs a UK Sleep Assessment and Advisory Service, when he spoke to the BBC about sleeping positions. Likewise, Dr Idzikowski added, foetal sleepers tend to be quite personable, even if they come off as shy upon first meeting people. More than twice as many women as men tend to adopt this position.