Do Sleep Trackers Work? An Expert’s Opinion
It’s not uncommon these days to see people walking down the street with a FitBit or an Apple Watch. These wearables can track a slew of things: your steps, calories burned, your heart rate. They also can track your sleep.
But what does that mean? And is the data it collects valuable in any sort of way?
Christopher Winter, MD, has been asking this question for years. Winter is an American sleep researcher, neurologist and author. Long before more than 60.5 million people started using wearables in the U.S. (that’s nearly 1 in 5 people), Winter was asking himself just how reliable sleep trackers and apps are.
His determination: It’s complicated.
In 2014, he published an article with the Huffington Post examining how well these tools worked. He measured data from his own sleep cycle against five different trackers. He found that some worked better than others to track his sleep and produce somewhat reliable data. His experiment was replicated in 2017 by then-Brown University student Jina Yoon.
She found similar results: Some wearables delivered more accurate and detailed data. But for Winter and Joon, something much larger became apparent. Even if the data was relatively good, it was only valuable if it was interpreted correctly. Moreover, it was important to consider what the patient was looking to do with said data.
“I do think they work,” Winter said in an interview AAST this February. “I think the biggest issue is really surrounding why the patient is buying it and what they’re hoping to get out of it.”
While wearables can telling someone a lot about their sleep—how much they’re moving, when long they're sleeping, etc.—that information is only useful when put into the scope of how it’s meant to be used.
Say, a college student wants to use it to measure how much they’re sleeping to determine whether they need to adjust their sleep schedule. A FitBit or Apple Watch might be the perfect solution. But if someone is using it to self-diagnose a sleep issue, it won’t work.
That’s because a fitness tracker is tracking one or two aspects of a sleep test. Sleep trackers only take a small subset of data, which in turn is not interpreted by experts. Winter likened it to someone installing an MRI in their home.
“Let’s say Apple comes out with their home MRI. It’s really good, it’s not that expensive and you can just stick it in your basement,” Winter said. “I’m not sure how helpful it would be without the expert.”
A polysomnogram, on the other hand, registers several data points which is reviewed by those trained to identify possible problem areas. Winter said that is particular important, because certain data points overlaid among others can signal serious health problems, and not those solely associated with sleep disorders.
“The technology works, and is getting better all the time,” Winter said. “It might even rival the same technology we use during a sleep study, but the sleep study has a lot more data points. It can really tell us what’s going on. We say the gold standard is a sleep study.”
So what can those working in sleep medicine do to help their patients interested in wearing these? Winter suggests not diminishing wearables as a whole, but encourages sleep medicine practitioners to instead talk through what a patient wants to do with a wearable.
“They do a good job of acting as a sleep diary. Every now and then I can check in, ‘Am I getting enough sleep?’ That’s where there’s power,” he said. “The technology is better if it comes with a little bit of expertise.”