By Sree Roy

Many patients have smartwatches up their sleeves. Indeed, the wearable technology market is booming in both style and substance; it’s predicted to experience a 11.28% compound annual growth rate through the year 2025, according to research firm MarketsandMarkets, which says preference for sophisticated gadgets and the growing popularity of the Internet of Things are two factors driving segment growth.1 

For now, consumer wearables are only relevant to sleep medicine to the extent that patients need reassurance that scoring a “perfect 100” on their sleep (as deemed by their smart device) isn’t worth stressing over or being aware that they need to remove the device during a sleep study to avoid artifact.

But manufacturers have more up their sleeves, and they are slowly revealing their upgraded capabilities. This year may be when several consumer wearables get US Food and Drug Administration (FDA) approvals for their sleep measurements.

One contender is Withings’ ScanWatch. According to Withings’ website, embedded light sensors will allow the device to interpret “the changing blood color within your vessels to determine oxygen saturation level in real time,” and Withings hopes that “when the Overnight Scan feature is activated, ScanWatch can help to reveal whether sleep apnea episodes have occurred.” Withings PR told tech website CNET that the watch is “currently going through the FDA and CE clearance approval processes for both ECG and sleep apnea detection.”2

Fitbit is also working on sleep apnea-related measurements. It has built-in SpO2 sensors and a new “estimated oxygen variation” feature. A Fitbit spokesperson told tech site Gizmodo, “Fitbit is continuing to collect clinical data to test and develop FDA-cleared features for sleep apnea. They expect to submit for FDA clearance soon and are maintaining a dialogue with the FDA throughout this process.”3

Meanwhile, several wearables have undergone validation testing. 

Investigators at the University of Arizona Health Sciences Center for Sleep and Circadian Sciences used the “WHOOP Strap 3.0” in a study that tested the wearable against polysomnography (PSG). “This study shows that the accuracy of WHOOP in measuring heart rate, heart rate variability, and sleep staging of slow wave and REM or dream sleep was excellent when compared to polysomnography,” says Sairam Parthasarathy, MD, professor of medicine at the UArizona College of Medicine – Tucson and director of the Center for Sleep and Circadian Sciences, in a release. The study found WHOOP to be within one heartbeat and breath per minute of PSG.4

And a study at the University of California – San Francisco Hypoxia Lab found Beddr SleepTuner to be accurate for measuring oxygen saturation levels with an error margin of +/- 2.2% when compared to an arterial blood draw.5

By the end of 2020, when a patient expresses concern about data collected by their smartwatch, reassurance may not be all that’s required. A more thorough look, possibly including a sleep study, may be just what the wearable ordered.


  1. Wearable technology market worth $56.8 billion by 2025 with a growing CAGR of 11.28%. 2019 July 5.
  2. Stein S. Withings’ new health watch can check for sleep apnea. 2020 Jan 5.
  3. McGarry C. Fitbit really wants to be able to diagnose your sleep apnea. 2020 Jan 15.
  4. Berryhill S, Morton CJ, Dean A, et al. Effect of wearables on sleep in healthy individuals: A randomized cross-over trial and validation study. J Clin Sleep Med. 2020 Feb 11.
  5. Accuracy of pulse oximeters with profound hypoxia. Identifier: NCT03710980. 2018 Oct 18.