Sleep Apnea
Sleep apnea is a condition causing the airway to become obstructed during sleep and airflow into the lungs is diminished or stops completely.
Usual causes of obstruction are enlarged tonsils and/or adenoids, loss of muscle tone in the neck during certain stages of sleep or excess fatty tissue in the neck area. During the obstruction, it is not unusual for the oxygen level in the blood to decrease. The pattern of obstruction, awakening with a loud snort to re-open the airway and then the obstruction happening again, repeats itself many times during the night.
This constant sleep/wake cycle leaves you feeling exhausted the next day even though you allowed sufficient time for a complete night of sleep
Watch this video about Obstructive Sleep Apnea: