Armin Rahmani, MD FRCPC DRCPSC
Sleep Medicine and Psychiatry
Member-at-Large, Canadian Sleep Society
Markham Stouffville Hospital
“My watch says I barely got any deep sleep last night—should I be worried?”
As a sleep physician, I hear this question all the time. More and more people are turning to wearable technology to track their sleep, hoping for better rest and improved health. With nearly 30% of Canadians using devices to monitor their well-being, sleep tracking has become one of the most popular features of wearables.
Wearable technology has quickly moved beyond fitness tracking and into the world of sleep monitoring. Many of today’s top devices—like the Apple Watch, Samsung Galaxy Watch, Garmin Watch, Oura Ring, and Whoop wristband—promise to reveal not just how long you slept, but how well. They provide charts, sleep scores, and detailed breakdowns of different sleep stages, offering a sense of control over something as mysterious as sleep.
But how reliable are these insights, and do they actually help you rest better—or just give you more to worry about?
Let’s take a closer look at what the research actually says.
What the Research Tells Us
New wearable devices and algorithms hit the market every year, but research takes time to catch up. As a result, it’s still difficult to determine just how accurate sleep trackers really are. Here are three key takeaways from current studies:
- Tracking Total Sleep Time
Wearable devices do a fairly good job at estimating how much sleep you get each night. Studies suggest they are accurate within about 10% of actual sleep time. This means if your tracker says you slept for seven hours, your real sleep time could be anywhere between 6 hours and 20 minutes to 7 hours and 40 minutes. - Measuring Sleep Stages
This is where things get tricky. Most wearables claim to track deep sleep, light sleep, and REM sleep, but studies show they can misclassify sleep stages. In other words, if your watch tells you that you only got 30 minutes of deep sleep, that number may not be very reliable. That said, newer devices are showing some improvements in this area. - Sleep Scores and Algorithms
Many devices provide a nightly sleep score—often a number out of 100 or a rating like “good” or “poor.” However, these scores rely on proprietary algorithms that aren’t always backed by strong scientific evidence. In some cases, they may even contribute to more anxiety about sleep rather than improving it.
Can Sleep Trackers Improve Sleep?
Here’s the paradox: in most areas of life, gathering more data helps us improve. But sleep is different.
Sleep is a passive process—you can’t force yourself to sleep better by trying harder. In fact, the more you focus on sleep, the harder it can become to get good rest. This is why we see a phenomenon called “orthosomnia”—a form of insomnia that develops when people become overly fixated on their sleep tracker data. Essentially, worrying about sleep numbers can lead to worse sleep.
How to Get a Better Night’s Sleep
Instead of obsessing over sleep tracker data, focus on building healthy sleep habits. Here are five simple ways to improve your sleep naturally:
- Stick to a consistent wake-up time. Waking up at the same time every day—even on weekends—helps regulate your body’s internal clock and improve sleep quality over time.
- Create a relaxing bedtime routine. Wind down with calming activities like reading, stretching, or deep breathing before bed. Avoid screens at least an hour before sleep.
- Make your sleep environment ideal. Keep your bedroom cool, dark, and quiet. Invest in a comfortable mattress and pillows that support good sleep.
- Limit caffeine and alcohol. Avoid caffeine in the afternoon and alcohol close to bedtime, as both can disrupt sleep quality.
- Get natural light and exercise. Exposure to daylight during the day and regular physical activity can help regulate sleep patterns—just avoid intense workouts too close to bedtime.
The Bottom Line
Sleep trackers are here to stay, and they’re only going to get better. While they can provide useful insights into how much sleep you’re getting, they aren’t always reliable when it comes to sleep staging or quality assessments.
Ultimately, the best sleep tracker is your own body. If a device helps you recognize sleep patterns and build better habits, great. But if it’s adding stress, it’s okay to trust how you feel over what a watch tells you.
To learn more, visit css-scs.ca.
