1. The sufferer falls asleep.
2. Muscle tone in the body relaxes.
3. The airway narrows and/or collapses, causing breathing to be difficult or impossible. The collapse of the airway may cause loud snoring, snorts, pauses in airflow, and labored breathing.
4. Oxygen levels begin to fall.
5. They continue to struggle for breath, sometimes for up to a minute.
6. The heart rate falls below normal, and there is decreased oxygenated blood to pump through the body.
7. The brain senses low oxygen/high carbon dioxide levels and releases jolt of adrenaline in an attempt to awaken their brain and body and prevent suffocation.
8. The sufferer awakens briefly and takes five or six large breaths breathing in oxygen and blowing off excess carbon dioxide (CO2). The sufferer typically does not remember arousal but often repositions him or herself on the bed.
9. The heart rate speeds up in response to the rush of adrenaline and is now pumping above normal heart rate.
10. The oxygen/carbon dioxide levels return to near normal and their brain allows sleeping to resume.
11. The sufferer falls asleep and the cycle repeats.
