What is sleep paralysis and why does it happen?

Short Answer

Sleep paralysis is a brief episode where you’re conscious but can’t move, typically while falling asleep or waking. It happens when REM muscle atonia persists into wakefulness, sometimes with vivid hallucinations.

Why This Matters

Sleep paralysis can feel terrifying because the brain’s threat system is active while the body remains “locked” in REM immobility. That mismatch leads to panic, chest pressure sensations, and intense interpretations of the experience. Understanding the mechanism reduces fear, which often shortens episodes and prevents a feedback loop of anxiety-driven sleep disruption.

Where This Changes

Episodes are more common with sleep deprivation, irregular schedules, sleeping on your back, and high stress. If paralysis is frequent, includes sudden daytime sleep attacks, or severely disrupts life, it can be worth discussing with a clinician to rule out narcolepsy or other sleep disorders.