Loud snoring Periods where breathing stops (usually noticed by another person) Gasping for breath during sleep Dry mouth Headaches the following morning Difficulty staying asleep during the night (insomnia) Excessive daytime sleepiness Problem with the attention span Irritability Sleep apnea sufferers may also experience a variety of additional symptoms. The first symptom is dizziness, which is caused by low oxygen levels. Night sweats, frequent nightly urination, and sexual dysfunction are all possible side effects for some people. Learn more in our blog article, "Sleep Apnea: Causes, Types & Treatments."