Sleep apnea is a sleep disorder in which your breathing is repeatedly interrupted during sleep. Sleep apnea can cause high blood pressure, depression, mood swings, personality changes, irritability, abnormal heart rhythms and an increased chance of heart attack. The most common telltale sign of obstructive sleep apnea is loud snoring, but not everyone who snores suffers from obstructive sleep apnea. If you or your bed partner suspect sleep apnea, talk to your doctor without delay.