Obstructive sleep apnea associated with impaired exercise capacity

Exercise testing may provide early window into heart disease risk of sleep apnea patients

A new study shows that obstructive sleep apnea is associated with impaired exercise capacity, which is an indicator of increased cardiovascular risk.

Results show that the predicted peak oxygen uptake, a measure of aerobic physical fitness, was significantly lower in people with moderate to severe obstructive sleep apnea than in controls. Further analysis found that sleep apnea severity alone explained 16.1 percent of this variability.

"We found a significant association indicating that there is likely a very strong independent relationship between obstructive sleep apnea and exercise capacity," said lead author Dr. Jeremy Beitler, assistant clinical professor in the Division of Pulmonary and Critical Care Medicine at the University of California, San Diego. "Based on our findings, future studies are warranted to evaluate the utility of cardiopulmonary exercise testing for cardiovascular risk stratification in patients with obstructive sleep apnea."

The study results are published in the Nov. 15 issue of the Journal of Clinical Sleep Medicine, which is published by the American Academy of Sleep Medicine.

"Obstructive sleep apnea is a chronic disease that increases the risk for heart problems such as high blood pressure and heart failure," said AASM President Dr. Timothy Morgenthaler. "For the best possible clinical outcomes, people with heart disease should discuss their risk for sleep apnea with their doctor."

The AASM reports that obstructive sleep apnea (OSA) is a common sleep illness afflicting at least 25 million adults in the U.S. Sleep apnea warning signs include snoring and choking, gasping or silent breathing pauses during sleep. The National Healthy Sleep Awareness Project, which is led by the AASM and funded by the Centers for Disease Control and Prevention, urges anyone with symptoms of sleep apnea to visit http://www.stopsnoringpledge.org to pledge to "Stop the Snore" by talking to a doctor.

The study involved 15 adults with moderate-to-severe obstructive sleep apnea and 19 controls with mild or no sleep apnea. All subjects were evaluated for sleep apnea during an overnight, in-lab sleep study. Cardiopulmonary exercise testing was performed on a stationary bicycle using a ramp protocol. Predicted peak oxygen uptake (VO2) was calculated as the maximum oxygen uptake in the final 20 seconds of exercise before exhaustion.