Is 87 blood oxygen normal?
If you're awake and feel short of breath, confused, or your lips look gray or blue, call 911. Awake at 88 or lower, get medical care now. As a watch night average, under 90 is a reason to talk to your doctor, especially if it repeats.
Awake and resting, 88 or lower means get medical care now (MedlinePlus).
Values that stay under 90 point to low oxygen (Shapiro 2023). At sea level that's under the 1st percentile, and in Denver under the 1st.
In 350 people with normal sleep studies, the lowest point of the night averaged about 90, and most stayed between about 84 and 97.
The device. A cleared finger oximeter can be off by about 3 points, a watch by about 2, and more when oxygen is low: below 88, an Apple Watch Series 7 was off by about 6 in 9 young adults.
Elevation. At Denver's 5,280 feet, a typical watch night sits about 1.9 points lower and a typical day about 1.4 lower. Above 8,200 feet the number can't tell you if you're getting sick, and symptoms decide.
Is it normal for oxygen to drop to 88 while sleeping?
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5 sources
- MedlinePlus, Pulse Oximetry, US National Library of Medicine, updated September 12, 2024medlineplus.gov
- Shapiro I and others, Pulse oximetry values from 33,080 participants in the Apple Heart and Movement Study, npj Digital Medicine, 2023pmc.ncbi.nlm.nih.gov
- Gries RE and Brooks LJ, Normal oxyhemoglobin saturation during sleep, Chest, 1996europepmc.org
- Sjoding MW and others, Racial bias in pulse oximetry measurement, New England Journal of Medicine, 2020pmc.ncbi.nlm.nih.gov
- Jiang and others, an Apple Watch Series 7 and a medical-grade finger oximeter against blood tests in 9 healthy adults under controlled low oxygen, 2026pmc.ncbi.nlm.nih.gov
