Does the sleep tracking feature on my smartwatch have any value?

Smartwatches measure your sleep by tracking movement and heart rate, and compare that with the gold standard in sleep research: a full measurement at a sleep clinic where brain waves, breathing and muscle tension are recorded simultaneously. How well that comparison holds up varies considerably by brand and model. A review of 16 smartwatches concluded that some devices achieve high accuracy with solid validation studies, while others effectively produce random results. No official standards currently exist to make a fair comparison between the two.

For everyday home use and athletes, smartwatches offer the best balance between price, ease of use and reliability compared with smartphone apps alone. That said, this is not the same as medical-grade quality: no consumer device is currently validated to a sufficient clinical standard to diagnose sleep disorders such as sleep apnoea. If you suspect sleep apnoea or another sleep disorder, a referral to a sleep clinic is necessary.

Interestingly, wearable data, including sleep data combined with step counts and heart rate trends, has already shown some value in early research for detecting depressive episodes. Across four small studies, prediction accuracy ranged between 81 and 91 percent. That sounds impressive, but the sample sizes were small, follow-up was short and the methods vary considerably. This is therefore a promising direction, but certainly not yet a reliable tool in practice.

In cancer patients, sleep data from wearables proved helpful in detecting side effects and mapping health patterns. These are associations, not diagnostics. In practical terms, your smartwatch is most useful as a personal trend monitor: if you notice poor sleep week after week, that is a signal to discuss your lifestyle or symptoms with your GP, not a replacement for a clinical measurement.