-
Reduced Vertebral Artery Flow: When the neck is tilted at an extreme angle for prolonged periods, it can mechanically compress or kink the vertebral arteries in the neck. Studies using Doppler ultrasound have shown significant reductions in vertebral artery blood flow in positions of extreme neck rotation or extension.
-
Increased Sleep Apnea Severity: The supine position allows the tongue and soft tissues of the throat to collapse backward more easily, worsening Obstructive Sleep Apnea (OSA). OSA causes repeated oxygen drops and blood pressure spikes throughout the night, directly increasing stroke risk through inflammation, endothelial damage, and atrial fibrillation.
-
Impaired Cerebral Venous Drainage: Lying flat can hinder the return of deoxygenated blood from the brain, potentially increasing intracranial pressure over time—a concern for those with vascular fragility.
-
The Blood Pressure Paradox: For some with certain forms of orthostatic hypertension, back sleeping can lead to higher nocturnal blood pressure compared to side sleeping.
Who Is Most at Risk?
This position is especially dangerous for seniors with: