Sleep Apnea Therapy Also Reduces Blood Pressure

Both daytime and nighttime blood pressure (BP) are reduced in patients with obstructive sleep apnea (OSA) who use continuous positive airway pressure (CPAP) therapy, according to a new study.

Researchers from the University of California San Diego (UCSD, CA, USA) compared the effect of two weeks of CPAP versus sham-CPAP versus supplemental nocturnal oxygen on 24-hour ambulatory blood pressure in patients with moderate to severe OSA. A total of 46 patients between the ages of 25 and 65 years were included in the study. The three groups had similar rates of compliance with therapy.

Two weeks of CPAP therapy led to significant reductions in nighttime systolic (6 mm Hg), mean (5 mm Hg), and diastolic (4 mm Hg) BP. Two weeks of CPAP therapy also resulted in significant declines of 3 mm Hg in daytime mean and diastolic BP. Sham-CPAP resulted in a 3 mm Hg rise in nighttime systolic BP, while nocturnal supplemental oxygen therapy did not have any significant effect on BP, despite improving oxyhemoglobin saturation. The findings were published in the May 2006 issue of Hypertension.

"That the fall in nighttime blood pressures was more substantial is itself relevant to preventing the consequences of hypertension, because high nocturnal blood pressures have been increasingly linked to adverse cardiac and vascular events,” said lead author Dr. Daniel Norman and colleagues of UCSD. "The small change in daytime blood pressure complements further the overall reduction in blood pressure burden.”

Obstructive sleep apnea syndrome (OSAS) is a debilitating sleep and breathing disorder defined as the cessation of breathing for 10 seconds or more at least five times per hour of sleep. During sleep, the body's muscles relax, which can cause excess tissue to collapse into the upper airway and block breathing. Repeated apneas and arousals deprive patients of REM and deep-stage sleep, leading to chronic daytime exhaustion and long-term cardiovascular stress.


Related Links:
University of California San Diego