Wearable devices have pulled terms like ‘REM sleep’ from scientific literature to daily discussion points. But what can people really learn from sleep trackers? — Photo by Chris Abney on Unsplash
Even just a decade or so ago, patients looking for answers to their sleep issues would need to undergo an overnight sleep study in a lab, hooked up to brain and breathing monitors.
These days, when patients arrive at appointments with sleep medicine doctors, they often arrive armed with data they've collected on their own, courtesy of small devices on their fingers or wrists.
"People come in every day to the clinic with either data on their iPhone or printouts from their Oura ring, Apple Watch, whatever type of wearable," said Ryan Soose, a UPMC sleep medicine doctor. "It's certainly increasing awareness."
Wearable devices have pulled terms like "REM sleep" from scientific literature to daily discussion points. But what can people really learn from sleep trackers?
Medically, they really can be useful, said Soose, who is also division chief for sleep medicine at the University of Pittsburgh School of Medicine.
In September, the Food and Drug Administration approved the newest Apple Watches, the series 10, to detect sleep apnea through a "Breathing Disturbances" function. Other non-Apple Watch devices can also alert users to breathing changes during sleep, though their accuracy has not been tested in clinical trials.
"There is a risk of false positives and a risk of over-interpretation," said Soose. "Just because a wearable is suggesting that something is off doesn't mean it's medically worrisome but you should at least talk to your doctor."
When Christopher Pham, a sleep medicine physician with AHN, sees patients who come in alarmed about findings on their wearable devices, he urges them to consider other indicators as well. How do they feel when they wake up? Are they taking longer naps? Having trouble concentrating?
"I usually tell people, 'You should take it with a grain of salt,'" he said. "The technology keeps getting better and is going to get more accurate, but you also want to have the caveat that the numbers might not reflect the true time frame."
For people who aren't concerned about a medical issue, but just want to use their wearable device to optimize their sleep, the numbers can be tricky. Some of the devices give a "sleep score," but that number doesn't necessarily mean that there's something wrong – or right – about one night of sleep.
"There's truly no consequence to a single number you are looking at," said Pham. "Everyone has so much nuance to how much sleep they actually need. Because of that variability, it's hard to tackle this."
The greatest use for an individual's sleep score is to use that number – and other metrics from a sleep tracker – to assess how changes in behavior are affecting sleep. It's worth tracking what happens to their sleep after someone gets nasal surgery, tries lip tape or stops drinking alcohol, said Soose, but that number isn't useful for comparing to someone else.
Other changes to sleep that can be assessed with wearable devices are switching from back sleeping to side sleeping, or adding a pillow to back sleeping, said Larry Chancellor, manager of respiratory care and the sleep disorders center at St. Clair Hospital. They can also change their lighting, possibly using a sleep mask and adjust background noise, he said.
Sleep trackers also provide data broken down throughout the night on light sleep, REM sleep and deep sleep, but Soose warns users against putting too much stock in that information.
REM sleep, named for the rapid eye movements during that period, is the period of sleep where most dreams happen. Deep sleep is when the body is most relaxed, and is associated with tissue growth and repair. Those sleep cycles are assessed in a sleep lab using brainwave monitors, said Soose, and while wearable devices do their best to assess them based on data such as heart rate, blood flow and oxygen, they may not be completely accurate.
"I would caution the patient not to overinterpret that," said Soose. "If someone has a wearable telling them that their REM sleep is a little low but they feel fine and function fine, I would let the symptoms be the driver of the findings."
Overall, said Soose, the impact of wearables is positive – especially when they can alert users to medical problems such as sleep apnea. But this much data can also be taken too far.
"We do have some patients who take it such to the extreme. They focus so much on their sleep data that they don't sleep well," said Soose. "The point is not to overthink it." – Pittsburgh Post-Gazette/Tribune News Service