Quick read: Sleep apnea and bleeding in the brain

In this 2025 study, moderate to severe obstructive sleep apnea had over 2x greater risk of cerebral microbleeding, which is associated with dementia and stroke.

Several other studies and meta-analyses support these findings:

If you haven’t been tested for sleep apnea before, I think it’s a good idea. People don’t always know they have it, and it’s often fairly easy to resolve.

Modern consumer wearables are getting better at detecting severe obstructive sleep apnea, but they lag behind professional-grade devices for detecting moderate OSA1, which is still associated with these microbleeds.

Apple Watches have been shown to only have 50.5% sensitivity to sleep stages, with wild inaccuracy at detecting both light and deep sleep.

Fitbit wasn’t great either, albeit better than Apple, and Oura rings did pretty well2, but your best bet is still to engage with a sleep specialist.

  1. Scanning of obstructive sleep apnea syndrome using smartwatch: A comparison of smartwatch and polysomnography ↩︎
  2. Accuracy of Three Commercial Wearable Devices for Sleep Tracking in Healthy Adults ↩︎

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