In the 1970s, psychoanalyst Samuel Dunkell proposed a curious, albeit almost completely unsubstantiated theory that the position you sleep in reflects your personality.
For example, preferring to snooze in the so-called royal position indicated self-confidence, while sleeping semi-fetal meant you're sensible and well-adjusted.
While Dunkell's ideas lack any definitive proof, how we sleep can impact our health.
So what's the best position to sleep in?
Sleep positions go by countless creative names: the zombie, mountain climber, free faller, and soldier.
Yet sleep experts typically simplify them into four basic types: left side, right side, stomach, or back.
Until the age of one, it is recommended that babies sleep on their backs to lower their risk of choking and suffocation.
As young children, we start to move around more in our sleep, usually ending up on our sides and backs, and this tendency to avoid sleeping on our stomachs only grows with age.
By adulthood, most people prefer side sleeping, while fewer favor back sleeping, and stomach sleeping is the least preferred overall.
But of course, individual sleep styles are highly personal.
