Air Force-Funded "Smart Pajamas" Track 6 Body Positions That Impact Sleep

Are you a fetus, log, yearner, soldier, freefaller, or starfish?

Sleep quality is important for stress management and mental health, but most people don’t know how to sleep better. For starters, most of us don’t even know how we sleep: Splayed out face first on the mattress? Curled up into a neat fetal position? “Smart pajamas” unveiled at the meeting of the American Chemical Society on Monday are helping answer that question in hopes of preventing people from sleeping the wrong way.

Trisha Andrew, Ph.D., an associate professor of chemistry at the University of Massachusetts Amherst, unveiled “smart pajamas” developed in part with a grant from the United States Air Force Office of Scientific Research. Andrew’s smart pajamas track the wearer’s sleep in intimate detail, measuring metrics like heart rate and breathing as well as identifying which of six common body positions a person maintains while they’re asleep. During a press conference in Orlando, Andrew explained how these new metrics can help make sleep better.

“If I ask you how you’re eating you know that. You can monitor that if you want. But if I ask you how you’re sleeping at night, that’s fairly personal information about yourself, and you don’t know the answer to that,” she said.

smart pajamas
"Smart Pajamas" with the lining open, showing the hardware underneath. 

What Information is Useful in a Sleep Sensor?

The smart pajamas feature five different sensing panels, sewn into the lining, that are intended to measure three different details: heart rate, breathing patterns, and sleep posture. While other smart garments or watches measure heart rate, posture is a unique feature of the pajamas. The pajama shirt, in particular, can distinguish between six different sleep positions: “the fetus,” “the log,” “the yearner,” “the soldier,” “the freefaller,” and the “starfish.”

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The six sleeping positions tracked by Andrew's smart pajamas 

“Monitoring breathing in general during sleep is how you detect sleep apnea, other sleep disorders and duration of REM sleep,” Andrew explained to Inverse after her presentation. “Sleep posture affects these things.”

The six sleep positions were originally defined by director of the Edinburgh Sleep Center, Christopher Idzikowski, Ph.D., in a 2003 survey. At the time, Idzikowski reported that 41 percent of 1,000 people in his survey sleep in the fetus position, 15 percent in the “log” position, 13 percent in the “yearner” position, 7 percent in the “freefaller” position, and 5 percent in the “starfish: position. (He also proposed that these sleeping positions were associated with personality traits, but that finding is inconclusive at best.)

Andrew makes it clear that these six positions may not mean much on their own. The most important effect they have on sleep is on a person’s ability to breathe: If sleep posture impacts breathing, then it could disrupt sleep quality. Her pajamas are designed to detect both.

In particular, they could be helpful for people with sleep apnea, a sleep disorder where breathing can suddenly stop during the night and make it very difficult to get a full night’s rest

“Not only are we telling you which position you’re sleeping in, but when you correlate that to your breathing that tells you, ‘Okay, in this position I’m getting more apnea’, or ‘I’m starting out in fetus, which is what everyone recommends you sleep in, and then for some reason at night you’re going freefaller, which actually inhibits and hinders your breathing at night,’” Andrew said in her presentation. “So you can start to find corrective ways to help you sleep better.”

“Corrective Ways to Sleep Better”

Finding the perfect sleep position that allows for unencumbered breathing may be the beginning of maximizing sleep — particularly for people who suffer from sleep apnea. To that end, some research has suggested that supine sleeping posture is correlated with more aggressive sleep apnea, but posture isn’t everything.

Carl Bazil, Ph.D., the director of Columbia University’s Sleep Disorders Center, is skeptical of the importance of sleep position for most people. “Position is rarely important except with a subset of patients with sleep apnea,” he tells Inverse. “And there are better ways of doing this.”

Even Andrew herself notes that improving sleep won’t come down to switching between, say, freefaller position or yearner position. “There is no ‘good’ or ‘beneficial’ posture,” she says. “It’s just information about yourself that you cannot otherwise collect by yourself.”

That said, there are some upsides to collecting data about ourselves even if its not clear how to use it just yet. Before consumer-based heart monitors were ubiquitous, for example, it may not have been obvious how knowing your heart rate during mundane daily activities, like watching horror movies, might help elucidate health either. But now, a specialized algorithm on the Apple watch designed using that data can detect heart conditions like atrial fibrillation.

Even if it’s not immediately clear what the average person can do with data about their sleep position or breathing rate in real time, Andrew believes that her technology may one day lead to “corrective ways” to sleep better. That’s a promise that many sleep-deprived people will be eagerly awaiting. In the meantime, her smart pajamas can tell you once and for all if you’re a starfish sleeper, a yearner or a free faller.