Can you trust gadgets to monitor your sleep? What scientists say

Smartwatches, fitness bands, and smart rings have become a common accessory for millions of people. Every morning, users check how much deep sleep they had, how many times they woke up during the night, and what their overall sleep quality score is. But how accurate are these numbers? The Associated Press spoke with experts and found that sleep trackers measure sleep only indirectly and should be treated with great caution.

How Sleep Trackers Work

Modern wearable devices do not determine sleep stages directly. Instead, they rely on indirect indicators such as body movements, heart rate, heart rate variability, and sometimes skin temperature. These data are processed by algorithms that try to estimate whether a person is asleep or awake and which stage of sleep they are in, such as light sleep, deep sleep, or REM sleep.

Sleep researcher Daniel Forger from the University of Michigan explained that algorithms are fairly good at identifying when a person falls asleep and when they wake up. However, estimating sleep stages is much more difficult. The accuracy is noticeably lower than in laboratory studies, where electroencephalography and other methods that directly measure brain activity are used.

Why the Numbers in Apps Are Not a Diagnosis

Neurologist Chantale Branson from Morehouse School of Medicine regularly encounters patients who come to appointments with printouts from their apps and feel anxious about having “bad” sleep. She said that this approach is misguided. Trackers are useful for observing trends, such as whether sleep is getting worse or becoming more stable over time. A single poor result by itself does not mean much.

She emphasized that basic sleep hygiene is far more important. This includes a regular sleep schedule, avoiding screens before bedtime, and keeping the bedroom cool and dark. If sleep problems persist, it is better to consult a doctor than to try to fix sleep based only on app numbers.

Practical Benefits and the Downside

Many users find real value in sleep trackers. An American teacher named Kate Stowey said that data from her smart ring helped her notice a connection between alcohol and poor sleep and understand that late dinners made it harder for her to fall asleep. For her, the device became a tool for changing habits.

However, there is also a negative side. Some people become overly focused on the metrics and feel anxious about low scores. This phenomenon has already been given a name: orthosomnia, which describes an obsessive pursuit of perfect sleep. In such cases, trackers cause more harm than good.

The Future of Wearable Devices

Despite their limitations, scientists believe that the potential of sleep trackers is far from exhausted. In the future, they may help detect infections at early stages, monitor sleep changes linked to depression, or warn about other health problems. But experts already agree on one thing: gadgets can suggest a direction, but final conclusions about sleep should be made by the person, preferably together with a medical professional.

In Brief

Smartwatches and rings measure sleep indirectly through movement, heart rate, and other signals rather than directly through brain activity. They are good at identifying when a person falls asleep and wakes up and at tracking general trends, but their accuracy in determining sleep stages is significantly lower than laboratory methods. Trackers are useful for monitoring habits but do not replace a doctor. Excessive focus on the numbers can lead to orthosomnia, which is anxiety caused by “bad” sleep scores. In the future, devices will become more accurate, but for now they should be seen as assistants rather than an ultimate source of truth.

Follow NEWS.am Tech on Facebook and Twitter