Is your deep sleep actually low — or is it just your device?
Before you spend another dollar trying to fix a number, find out whether the number is real.
Independent lab research comparing wearables against overnight clinical sleep studies has found real differences by device and device generation — correctly identifying anywhere from about 47% to 70% of clinically confirmed deep-sleep time depending on the brand and model, at the group level. Your own device’s number is a useful estimate to watch over time, not a lab result.
Source: Schyvens et al., 2025, Sleep Advances (doi.org/10.1093/sleepadvances/zpaf021); Khan et al., 2025, OTO Open (doi.org/10.1002/oto2.70181).
What you’ll get, free:
- What your specific tracker measures — and where it’s known to run high or low
- The realistic deep sleep range for your age, which is lower than the internet claims
- How to establish a seven-night baseline and calculate your own noise floor
- The three levers worth pulling before you buy a single supplement
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Loud snoring, witnessed pauses in breathing, or exhaustion that persists even after a long night point to something a decoder can’t solve. That is something a licensed physician should evaluate directly.
Flow BioLabs provides educational information only and does not provide medical advice, diagnosis or treatment. Nothing here is intended to diagnose, treat, cure or prevent any disease. Consult a licensed healthcare provider before beginning any new health protocol. Wearable sleep-stage figures are algorithmic estimates, not clinical measurements, and device accuracy figures cited reflect published population averages rather than guarantees about your individual device. © 2026 Flow BioLabs.
Looking for a different angle? Our Recover & Perform path — see the full guide → — may also be relevant.