Sleep Science

Your sleep
doesn't need a grade

By Colin Shepard Hanson · September 2026 · 9 min read

You wake up feeling fine. Then your watch gives last night's sleep a 62.

Nothing about the night has changed, but something about the morning has. The number is official-looking, specific, and difficult to unsee. You start searching your memory for the sleep it says you had instead of trusting the one you remember.

That is the problem with turning sleep into a score. A score can help you notice a pattern, but it can also become a verdict. And sleep is unusually vulnerable to being made worse by the effort to perfect it.

That is an argument, not a medical consensus. Sleep trackers can be useful, and the evidence does not show that they harm everyone. But the research gives us good reasons to treat a nightly score as an estimate, not as an objective grade on how well we slept.

What a sleep score actually measures

Your watch or ring does not observe sleep the way a laboratory does. A clinical sleep study uses electrodes and sensors to measure brain activity, eye movements, muscle activity, breathing, oxygen, and heart rhythm. Consumer devices usually infer sleep from a smaller set of signals such as movement, heart rate, temperature, and blood oxygen.

The device then applies its own algorithm and compresses several estimates into one number. Duration, timing, interruptions, heart-rate patterns, and estimated sleep stages may all contribute. Change the algorithm or its weighting and the score changes, even when the night does not.

That does not make the data useless. It means the precision of the display can exceed the precision of the measurement. An 82 looks exact. What produced it is a chain of sensor readings, estimates, classifications, and product decisions.

The American Academy of Sleep Medicine says consumer sleep technology can support a conversation with a clinician, but should not replace validated diagnostic testing. A score may identify something worth discussing. It cannot tell you that you do or do not have a sleep disorder.

The only-a-loss thought experiment

Imagine four possible mornings:

The point is not that every score is harmful. It is that the number earns authority very easily. Once it becomes the first thing you consult, your own experience can become secondary to an estimate made by a device.

Even the companies making these scores acknowledge the tension. Google's guidance tells users to focus on personal trends instead of chasing 100, and says to trust the body first when a low score conflicts with feeling rested.

Can a bad score actually make you feel worse?

There is evidence that beliefs about sleep can influence how people feel and perform, but it needs to be read carefully.

In a study of 63 people with insomnia, researchers gave participants fabricated positive or negative feedback about their sleep. By evening, the group given negative feedback reported less alert thinking and more sleepiness and fatigue than the group given positive feedback. Their objective sleep did not create the difference because the feedback was assigned.

An earlier pair of experiments involving 164 participants found that people told they had received below-average REM sleep performed worse on some tests of attention and verbal fluency than people told they had received above-average REM sleep. Their own rating of the previous night's sleep did not predict those results as strongly as the assigned feedback.

So the honest conclusion is not "a low score will ruin your day." It is that sleep feedback can shape experience for some people, particularly when sleep is already a source of worry. That is enough reason to notice what the score does to you, not just what it claims to measure.

Orthosomnia: when optimizing sleep becomes the problem

In 2017, sleep researchers coined the term orthosomnia to describe a perfectionistic pursuit of ideal sleep driven by tracker data. The name is now widely used, but it is not a formal medical diagnosis.

The original paper was a case series involving three patients, not a population study. The patients were preoccupied with improving their numbers, spent excessive time in bed, and sometimes trusted tracker output over clinical findings. The researchers warned that sleep trackers could reinforce anxiety or unhelpful behavior in a subset of people.

That distinction matters. "Orthosomnia exists" should not become another frightening score to give yourself. The useful question is simpler: is tracking helping you make a calm, useful decision, or is it making sleep feel like a test you can fail?

When sleep tracking can be useful

A tracker is most useful when it helps answer a specific question over time:

• Is my sleep schedule more consistent than it was last month?
• Do late meals or alcohol repeatedly coincide with a worse morning?
• Am I allowing enough time for sleep?
• Is there a persistent pattern worth discussing with a clinician?

Those are trend questions. They do not require treating one night's score as a diagnosis or a forecast for the day ahead. Trackers are weaker when they turn normal variation into a daily performance review, especially when they offer a score without a useful action.

And the score should never override persistent symptoms. If you regularly struggle to sleep, wake unrefreshed, feel excessively sleepy during the day, or have signs of breathing interruptions, talk with a qualified healthcare professional regardless of what the wearable says.

A less anxious way to use a sleep tracker

1. Check in with yourself first. Before opening the app, notice whether you feel rested, alert, and able to function.
2. Look for trends, not verdicts. A weekly or monthly pattern is more useful than reacting to every nightly score.
3. Connect data to a decision. If a metric cannot change anything you will do, consider whether you need to review it.
4. Run a tracker break. If the number creates anxiety, reassurance-seeking, or pressure at bedtime, try one or two weeks without checking it and compare how you feel.
5. Use symptoms, not scores, to seek care. Consumer data can support a clinical conversation. It should not replace one.

The bottom line

A sleep score is information. It is not a verdict, and it does not get to tell you how you feel.

If the score helps you notice a stable pattern and make a useful change, keep it in perspective and use it. If it makes you doubt a good morning, dread bedtime, or chase a perfect number, the most useful sleep feature may be turning it off.

Frequently asked questions

Are sleep scores accurate?

Sleep scores can be useful estimates of patterns, but they are not direct measurements of sleep quality. Accuracy varies by device, metric, software version, and the person wearing it. Sleep and wake detection is generally more dependable than detailed sleep-stage estimates.

What is orthosomnia?

Orthosomnia is a term researchers use for an unhealthy pursuit of perfect sleep driven by tracker data. It is not a formal medical diagnosis. It describes situations where monitoring and optimizing sleep numbers may increase worry or reinforce behaviors that make sleep more difficult.

Should I ignore a low sleep score if I feel rested?

One low score is not a diagnosis. Notice how you feel and consider the longer-term trend rather than letting a single number decide how the day will go. Persistent fatigue, sleepiness, insomnia, or breathing concerns are reasons to speak with a healthcare professional regardless of the score.

Can a sleep tracker make insomnia worse?

For some people, especially those already worried about sleep, tracker feedback may reinforce anxiety and unhelpful efforts to perfect sleep. Research has not shown that trackers cause insomnia for everyone. If checking the data increases worry, taking a break is a reasonable personal experiment.