Sleep Trackers: Helpful or Harmful?

If you’ve bought a sleep tracker, you probably want to understand your sleep patterns and improve the quality of your rest. But how accurate are these devices, and can they truly help—even if you have insomnia?

For people who haven’t paid much attention to their sleep before, trackers can be eye-opening. They can show the difference between time spent in bed and actual time asleep, highlighting when you’re not getting enough rest. This awareness can encourage better sleep habits.

But if you already have ongoing sleep issues—like difficulty falling asleep, waking often, or waking too early—the story is different. Data alone won’t solve the problem and may even make things worse by increasing anxiety about your sleep.

The NHS-recommended, evidence-based treatment for persistent sleep problems is Cognitive Behavioural Therapy for Insomnia (CBT-I), and this is something trackers don’t replicate. Instead, they rely on basic “sleep hygiene” tips, which research shows can sometimes make insomnia worse.

In addition, there are also some concerns around the accuracy of these devices. Sleep trackers can generally record time in bed fairly accurately, but they often struggle with more specific accuracies around things like:

·      Detecting wakefulness

·      Calculating total sleep time

·      Differentiating between sleep stages (light, deep, REM) 

They also tend to overestimate how long you sleep and underestimate time awake. If you lie still while awake—a common insomnia experience—the tracker might mark you as asleep. Accuracy can also be affected by factors like movement, heart rate, skin tone, and wrist positioning.

It's also important to be cautious about using sleep trackers if you are already struggling with your sleep. The reality is, if you have insomnia, you already know when you’ve had a bad night.

Seeing a low sleep score in the morning can make you dread the next night’s sleep, lowering motivation and increasing anxiety. This can lead to hypervigilance about sleep—one of the key drivers of insomnia. Some people even develop orthosomnia, where they become obsessed with achieving a perfect sleep score. This often results in spending longer in bed, chasing numbers, without improving actual sleep.

That’s why I often recommend my insomnia clients stop tracking their sleep altogether while working on recovery.

However, if you already have a sleep tracker, and want to keep using it, here are a few tips to do so without becoming obsessed:

·      Check weekly, not daily – This helps you spot trends without getting hung up on nightly numbers.

·      Trust how you feel – A score may not reflect how well you can function the next day.

·      Use with CBT-I strategies – Focus on resetting your body clock, building sleep drive, and reducing sleep-related anxiety. 

Sleep trackers can raise awareness of your sleep patterns, but they are not a fix for insomnia. The most effective way to improve long-term sleep is to follow evidence-based approaches like CBT-I, which tackle the root causes and support lasting change.

If you’ve been struggling with poor sleep, it may be time to put the tracker down and work on strategies that really make a difference.