Explore Sleep Apnea
When you're awake, throat muscles help keep your airway stiff and open so air can flow into your lungs. When you sleep, these muscles relax, which narrows your throat.
Normally, this narrowing doesn’t prevent air from flowing into and out of your lungs. But if you have sleep apnea, your airway can become partially or fully blocked because:
Not enough air flows into your lungs if your airway is partially or fully blocked during sleep. As a result, loud snoring and a drop in your blood oxygen level can occur.
If the oxygen drops to a dangerous level, it triggers your brain to disturb your sleep. This helps tighten the upper airway muscles and open your windpipe. Normal breathing then starts again, often with a loud snort or choking sound.
Frequent drops in your blood oxygen level and reduced sleep quality can trigger the release of stress hormones. These hormones raise your heart rate and increase your risk for high blood pressure, heart attack, stroke, and arrhythmias (irregular heartbeats). The hormones also can raise your risk for, or worsen, heart failure.
Sleep Disorders & Insufficient Sleep: Improving Health through Research
National Institutes of Health- (NIH) supported research is shedding light on how sleep and lack of sleep affect the human body. The NIH and its partners will continue to work together to advance sleep research. Read the full fact sheet...
The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.