My Oura ring says my sleep is great but I wake up exhausted every day. Which should I believe?

Your body. Every time. Wearable sleep assessment correlates reasonably with polysomnography for total sleep duration (within 20–30 minutes in most studies) and less reliably for sleep stage classification. The Oura ring's deep sleep detection has a sensitivity of approximately 54–65% against gold-standard polysomnography in validation studies, meaning it misses a substantial proportion of actual deep sleep events, and misclassifies some stages as well. If the ring says your sleep is great and you wake up exhausted consistently, the ring is wrong, you are right, and the discrepancy is worth investigating clinically.

The most likely explanation for the subjective-objective disconnect is obstructive sleep apnea: the ring has no reliable mechanism for detecting apneic events that fragment sleep architecture without producing movement artifacts large enough to register as arousals. A man with moderate OSA (15–30 apneic events per hour) gets technically adequate-duration sleep on the ring's measurement and genuinely unrestorative sleep in his body. The STOP-BANG questionnaire is the clinical first step. After that, a home sleep test. Your clinical experience of your own body is always the primary data. The wearable is a supplement to that, not a replacement for it. (Perez-Pozuelo et al., npj Digital Medicine, 2020)

Cardiologist's calibrated position, Early (3) for wearable sleep stage accuracy. The clinical credibility of your own symptom experience exceeds the algorithm's assessment when they conflict.

What to do: If you have persistent non-restorative sleep despite positive wearable reports: complete the STOP-BANG questionnaire and pursue a home sleep study before assuming the ring is correct and the symptom is psychosomatic.

For the full picture, read What Your Apple Watch Is Trying to Tell You.