Each night, Trixie, my miniature schnauzer, sleeps on her back, with her head cocked sideways and her front paws raised in the air as if she is in the middle of doing the wave. Nestled between my husband and me on a king-sized bed, Trixie's pink stomach is stretched out for anyone to see and perhaps rub (if I had to guess).
A fellow dog lover and amateur trainer once told me that this nocturnal position means that Trixie is an extremely trusting dog and feels loved.
Turns out, a similar philosophy also holds for humans. Research suggests that exactly how we sleep (position-wise) and how long we sleep can provide clues to our personalities and mental and physical status.
A study analyzing six common sleeping positions, including the fetal position and the "log" (lying on your side with both arms parallel to your torso and legs), found that each position is actually linked to a particular personality type.
For example, if you curl up in the fetal position when you sleep, you may be tough on the outside and soft on the inside. According to the research, this was the most common sleeping position; 41% of the 1,000 people in the study slept in the fetal position. More than twice as many women as men tend to adopt this position, according to sleep specialist Chris Idzikowski, PhD, a director of the Sleep Assessment and Advisory Service in London and the author of several books on sleep including Learn to Sleep Well.
Idzikowski's more recent research is again focusing on preferred positions and is cross-cultural to see if these initial findings hold. "The original United Kingdom data is compared with data collected from Australia, Japan, Hong Kong, China, and Singapore," he says. "The cross-cultural work has raised more questions."
One thing is clear, however. "If you sleep in a bad position, you're more likely to be grumpy the next day," he says.
According to his initial data, if you sleep like a log, at least positionally, you are typically easy going, sociable, and want to run with the A-list crowd. As a result, however, you may be gullible. People who sleep on their side with both arms out in front can be suspicious and cynical.
And if you know anyone who sleeps on their back with both arms up around the pillow (a.k.a. the "starfish"), you are in luck because such sleepers make good friends. They are always ready to listen and offer help.
Even a 'Starfish' Can Snap
But even a starfish can turn on you if they don't get enough sleep, experts tell WebMD
Sleep has "a huge effect on our personality and well-being because everyone has an individual need to sleep and if you are not able to meet your needs, you are not going to behave," says Ana Krieger, MD, director of the New York University Sleep Disorders Center in New York City. "Your normal way to compensate for the loss of sleep is by overworking, being rude or hyperactive, being more depressed and less social."
"With regard to personality, everybody knows that one of the first consequences of sleep deprivation is impaired sustained attention and irritability," says Mark W. Mahowald, MD, director of the Minnesota Regional Sleep Disorders Center at Hennepin County Medical Center and professor of neurology at the University of Minnesota in Minneapolis. "Just about any degree of sleep deprivation will result in irritability and has far-reaching ramifications in the workplace, family, classroom, and behind the wheel."
By contrast, delaying start times in schools so students get more sleep results in better behavior, he points out. "With more sleep, people are less irritable and less short tempered."
"Most of the studies show that when a person doesn't get enough sleep on a regular basis, there is a gradual deterioration of function, and the same thing is true if you disrupt sleep with lights, sounds, and bells," says Robert Ballard, MD, medical director of the sleep disorders program at National Jewish Hospital Medical Research Center in Denver.
But with adequate sleep, he says, there may be improvement in learning, memory, and reasoning. "People are capable of thinking more abstractly, better capable of problem solving, have improved fine motor coordination and long and short-term memory."
"What we know is that if people don't get as much sleep as they should, they have changes in their mood and their level of activity," agrees NYU's Krieger. For example, when kids get hyperactive and cranky, it means they are overtired and ready for a nap. "Adults just get moody and upset with everybody," she explains.
Poor Sleep Also Problematic
This can occur if they are not getting enough sleep or if they are getting poor-quality sleep, she says.
According to Krieger, "When people say 'I probably do sleep, but I don't feel rested and I worry at night and have a lot of stress,' this may suggest alpha [sleep wave] intrusion, which causes nonrestorative sleep disorder. With this condition deep sleep is interrupted by bouts of waking-type brain activity. In particular, people with the chronic pain disorder fibromyalgia tend to have a lot of alpha intrusion during the night.
What about too much sleep? "Most likely there is no such thing as too much sleep," she tells WebMD. "Patients that are depressed tend to sleep more, but we don't know what comes first. We are supposed to have more rapid eye movement (REM) sleep later in the night, but patients who are depressed have it earlier and for longer periods of time."
REM is the deepest stage of sleep; it is when intense dreaming occurs during sleep. During REM there is an increase in brain activity and many body-function changes occur, including an increase in breathing and heart rates.
What Time Is Your Internal Alarm Clock Set For?
Whether a person is up all night watching reruns of bad sitcoms and scary movies or sound asleep by 9 p.m. is based, in part, on his own internal alarm clock. And such clockwork may play a role in workplace success.
"A clock mechanism makes us sleepier at certain times and more alert at others, and it can make you want to stay up all night or go to bed quite early," Ballard says.
This can be a problem at times. "For instance, teenage boys who don't go to sleep until 3 or 4 a.m. may sleep through their classes, and if this persists into adulthood, they may have difficulty functioning in an early morning job," he says.
A study of middle school students showed that teens may also suffer from lower self-esteem and more depression when they don't get enough sleep.
Sleeping Style Affects Physical Health
How you sleep also affects your physical health. For example, the freefall position (lying on your front with your hands around the pillow and your head turned to one side) is good for digestion. But the "soldier" (lying on your back with both arms pinned to your sides) and the "starfish" may lead to snoring and a bad night's sleep.
"Some sleep positions are bad for health," Idzikowski tells WebMD.
Other research has shown that the breathing pauses of sleep apnea occur when a person sleeps on their back.
"If you have an underlying sleep disorder, body position may be significant," says Krieger. "Sleep apnea is worse when you sleep on your back, and other patients with leg cramps and restless legs syndrome have leg discomfort, so they tend to sleep in the fetal position and hold their legs."
Sleep apnea is marked by brief interruptions of breathing during sleep, while restless legs syndrome is characterized by an overwhelming urge to move the legs, usually due to uncomfortable or unpleasant sensations.
There are simple tips for improving sleep quality. However, talking with your doctor and letting him know what is going on may help. There may be an underlying medical problem causing these sleep-related problems.