Decreases in airflow can cause your blood oxygen levels to drop. Oxygen level drops are stressful for the heart, brain, and other organs. Severe sleep apnea has been linked to many health problems including depression, high blood pressure, diabetes, stroke risk, heart attack risk, and automobile accidents. Airflow decreases also cause disruptions from sleep because the brain needs to wake up to open up the airway. These repeated awakenings may cause some people to feel like sleep is not restful, leading them to be tired throughout the day.