Patients with sleep apnea are more likely to die from heart attacks at night, while sleeping, than in the day, which is the time when everyone else is most vulnerable, researchers have found.
Most heart attacks in the United States take place between dawn and noon, but sleep apnea -- marked by a tendency to snore, stop breathing and then startle awake -- changes this pattern, researchers said.
What is still not clear is how much sleep apnea raises the risk of premature death overall, they wrote in the March 24 issue of the New England Journal of Medicine. As many as one in four Americans suffers from some degree of apnea, in which the throat repeatedly closes during sleep, causing breathing to stop for 10 to 30 seconds and oxygen levels to fall dramatically. The condition, more common in men and the obese, causes stress on the heart and makes sufferers tired during the day.
The study of 112 Minnesota residents with diagnosed sleep apnea who died suddenly from cardiac causes found that more than half died between 10 p.m. and 6 a.m. -- usually the time when people are the least likely to die of heart problems. However, they were only half as likely to suffer a fatal heart attack between 6 a.m. and noon.