It's a sleep disorder that literally means "without breath," and for those who have it, getting a good night's rest can be difficult. But those with sleep apnea could also face a higher risk for strokes, according to a new study.

"We showed for the first time that if you have sleep apnea, your chance of having a stroke is four times greater than if you have no sleep apnea," Dr. Douglas Bradley, director of the Sleep Research Laboratory at the Toronto Rehabilitation Institute, told CTV News.

The researchers found that interrupted sleep increases blood pressure, which makes blood more prone to the clots that cause strokes. More than 70 per cent of stroke patients are later found to have sleep apnea.

Their work was published in the current issue of the American Journal of Respiratory and Critical Care Medicine.

According to the American Sleep Apnea Association, patients with sleep apnea can wake up hundreds of times a night, and the condition is as common as adult diabetes.

For Hugh Magnus, his sleep apnea used to be so severe that he would wake up 80 times an hour. To stop the problem, he was given a Continuous Positive Airway Pressure machine (CPAP) two years ago. The device pushes air into the lungs, regulating breathing.

"It was unbelievable. When I got the CPAP machine, I was sleeping 8 hours a night," he told CTV News. "I had never slept 8 hours in years!"

This fall, Magnus decided to try sleeping without the CPAP. His sleep apnea returned, and worse, within a month he suffered a massive stroke.

Magnus is convinced the stroke was caused by his sleep apnea.

"I stopped using (the CPAP) because I thought I could live without it. But I've learned the hard way," he said.

Bradley thinks more research into sleep apnea is crucial for helping patients like Magnus.

"I think sleep apnea is the new frontier for cardiovascular medicine, to be honest," he said.

It's an idea that Dr. Michael Hill, researcher for the Heart and Stroke foundation, agrees with.

"Sleep apnea is under-diagnosed. We should be looking for it, and if we found it, we could probably prevent strokes."

With a report from CTV's Avis Favaro