According to new research sufferers from sleep apnea, have double the risk of stroke or death.
Sleep apnea is a condition in which the throat closes off throughout the night, and normal breathing is interrupted.
Apparently as many as 4 percent of Americans suffer from extreme daytime fatigue because their sleep apnea forces them to repeatedly wake up if only for a second.
It seems another 16 percent of Americans have apnea without fatigue.
In their research the Yale University team also questioned whether existing apnea treatments reduced that risk.
The seven-year study, led by Klar Yaggi of the Yale University School of Medicine, found that people with apnea were twice as likely to die or have a stroke, and the risk more than tripled among volunteers with the worst apnea.
The study involved 1,022 people and showed that the risk persisted even with treatment to keep the throat open during sleep, mostly through a continuous positive airway pressure (CPAP) machine.
Other study volunteers lost weight or had surgery to ease their symptoms.
But Vaggi does say that despite the results of the study, the machines are still worth it for people with apnea that produces excessive fatigue.
He says they now realise that sleep apnea is an independent risk factor for cardiovascular disease, for high blood pressure, for heart disease, and also for stroke.
He believes that treatment will help to reduce the cardiovascular risk.
In a separate Canadian study it was also found that breathing machines used to treat a form of apnea common in people with heart failure did not prevent death or the need for a heart transplant.
The Canadian study evaluated 258 people with central sleep apnea, where fluid in the lungs caused by heart failure makes sleepers hyperventilate, which temporarily prevents the accumulation of enough carbon dioxide to trigger the breathing reflex.
Basically people forget to breathe.
About one third of the 5 million Americans with heart failure also have central sleep apnea.
Douglas Bradley of the University of Toronto and his colleagues said they were surprised to find that heart failure patients with apnea who used CPAP machines were just as likely to die or receive a heart transplant as those who went untreated.
In fact, in the early part of the study, people breathing through CPAP machines seemed to fare worse.
Bradley says that heart failure patients are given the machines to drive water out of the lungs and reduce the work of breathing, and they also may help the heart beat more effectively.
Although using the machines during the 5-1/2-year study did not help patients live longer, they did improve the efficiency of the heart and allowed patients to exercise more.
Both the studies are published in The New England Journal of Medicine.