CPAP treatment restores brain stem function, reverses health changes linked to heart disease

Continuous positive airway pressure (CPAP) machines are a commonly prescribed treatment for obstructive sleep apnea, a disorder in which muscles in the airways collapse during sleep, blocking breathing. A CPAP machine keeps the airways open by delivering forced air through a mask a person wears while sleeping. Because of the design, however, some people have a hard time getting used to the machine and do not continue the treatment or are reluctant to start. A new study in the Journal of Neurophysiology supports the use of CPAP as a sleep apnea treatment, finding that it reverses the health changes that result in cardiovascular disease if the disorder is left untreated.

Those with obstructive sleep apnea have greater activity of their sympathetic nerves—nerves responsible for ramping up the body to respond to stress—which has been shown to lead to hypertension and cardiovascular events. Previous studies have reported that the elevated sympathetic nerve activity is due to altered activity and structure of the brain stem, the region in the brain that regulates sympathetic nerve activity, and that CPAP treatment reduces the increased nerve activity. This study, conducted at the University of Sydney in Australia, found that the reduction in nerve activity occurred because CPAP treatment restored brain stem function. The researchers measured sympathetic nerve and brain activities and brain volume in patients with obstructive sleep apnea before and after six months of CPAP treatment.

"These data strongly suggest that functional and anatomical changes within the brain stem, which we believe underlie the elevated sympathetic activity in individuals with untreated obstructive sleep apnea, can be restored to healthy levels by CPAP treatment," the researchers wrote. The data "highlight the effectiveness of CPAP treatment in reducing one of the most significant health issues associated with obstructive sleep apnea," cardiovascular disease, according to the researchers.