The three-night check
One low night tells you very little. Three nights on the same device, the same way, tell you whether it repeats.
Sunday, November 15 to Tuesday, November 17
On an Apple Watch. Keeping the same: the same device, worn the same way, the same elevation, drinks kept the same, or skipped.
Night 1Sunday, November 15
Night 2Monday, November 16
Night 3Tuesday, November 17
On the fourth morning, this card tells you: one low night, or a pattern to bring to your doctor.
If your lowest number keeps dropping under 90, or someone has seen you stop breathing in your sleep, ask your doctor about a sleep study. Bring this card.
What your result means, and what to do next
- One low night means nothing to act on. Healthy sleepers' lowest point averaged about 90, so plenty of normal nights dip under it once.
- A pattern to bring to your doctor means the low points kept coming with everything held the same, or someone saw you stop breathing. Print the card and take it to the appointment, and ask about a sleep study.
How it works
Keep everything the same for three nights: the same device worn the same way, the same elevation, and drinks kept the same or skipped. In 20 men with no symptoms, one evening of drinking raised oxygen dips that night and they were still raised the next night, with no more alcohol.
Each morning, note the night's average and its lowest point, and anything that happened: drinks, sleeping on your back, snoring or pauses someone noticed, a morning headache, daytime sleepiness. Loud snoring, pauses someone saw and daytime sleepiness are among the signs doctors ask about before a sleep study.
On the fourth morning the card says one low night or a pattern. A pattern is the lowest point under 90 on all three nights, an average under 90 on two of them, or someone seeing you stop breathing. In 350 healthy sleepers the night's lowest point averaged about 90, so plenty of healthy nights dip under it once.
5 sources
- Taasan VC and others, Alcohol increases sleep apnea and oxygen desaturation in asymptomatic men, American Journal of Medicine, 1981europepmc.org
- Kolla BP and others, The influence of alcohol on breathing parameters during sleep, Sleep Medicine Reviews, 2018europepmc.org
- 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
- Chung F and others, STOP-Bang Questionnaire, Chest, 2016europepmc.org
