NEW YORK (Reuters Health) - Daytime sleepiness brought on by obstructive sleep apnea (OSA), a condition in which airways become blocked during sleep and breathing frequently stops for brief periods, may go hand in hand with heart problems, a report shows.

In a study of 86 adults with OSA but no other medical conditions aside from high blood pressure, a higher score on a standardized daytime sleepiness scale was independently associated with decreases in cardiac function, the researchers found.

The cardiac function in these patients was "subtly impaired," perhaps contributing to the perception of sleepiness and fatigue," Dr. Joel E. Dimsdale, of the University of California, San Diego noted in a statement accompanying a report of the study in the journal SLEEP.

"OSA is a common sleep disorder characterized by considerable daytime sleepiness and by increased cardiovascular disease," Dimsdale told Reuters Health.

"It has been known for a long time that apnea is associated with increased risk for hypertension (high blood pressure) and increased heart-related death. However the mechanism for this mortality has not been understood," he explained.

"The current study found that OSA patients with more complaints of daytime sleepiness had decreased effectiveness of the heart's pumping action," Dimsdale continued.

"In this sense, the sleepiness that our patients report reflects not just their sleep disruption but also may be a marker for undiagnosed cardiac problems," he warned. The findings highlight the importance of taking sleep disorders seriously, Dimsdale concluded.