Sleep Apnea May Cause Heart Attack at Night: Study

Sleep apnea could cause heart attacks to occur at night, Reuters reports. The disorder, in which breathing is temporarily blocked during sleep, causes changes in blood pressure and hormone levels that might increase arterial blockage, a new study published in the Journal of the American College of Cardiology finds.

Researchers monitored patients at high risk for heart attack, some of whom also had sleep apnea. Those with the sleep disorder were 6 times more likely to have a heart attack at night than during the day. Patients without sleep apnea had the majority of heart-attack symptoms during the day. (More sleep apnea stories.)