Sleep apnea is a condition where your breathing repeatedly stops or becomes shallow during sleep, often without you realizing it. These interruptions can lead to loud snoring, daytime fatigue, morning headaches, poor concentration, or waking up feeling unrested. Over time, untreated sleep apnea can put strain on your heart, raise blood pressure, and interfere with overall health. Many people don’t know they have it—only that they’re exhausted despite “sleeping” through the night.