HealthDay News —  Patients with obstructive sleep apnea (OSA) treated with continuous positive airway pressure (CPAP) appear to have decreases in basal metabolic rate (BMR), according to a study published in the American Journal of Respiratory and Critical Care Medicine.

Ryo Tachikawa, MD, PhD, from Kyoto University in Japan, and colleagues examined the mechanisms by which patients with OSA gain weight after CPAP initiation. A comprehensive evaluation of energy metabolism was conducted in 63 participants with newly diagnosed OSA (51 men), CPAP initiation, and 3-month follow-up. Participants underwent polysomnography, body weight, body composition, basal metabolic rate, hormones, dietary intake, eating behavior, and physical activity measurements.

The researchers found that after CPAP there was a significant decrease in BMR (P<.001), but no change in physical activity or total caloric intake. Baseline apnea-hypopnea index, change in urine norepinephrine, and CPAP adherence were identified as significant predictors for the change in BMR in multivariate regression. 

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Compared with non-weight gainers, weight gainers had higher leptin levels, lower ghrelin levels, and higher eating behavior scores. Increased caloric intake was a particularly significant predictor of weight gain among parameters related to energy metabolism.

“Although a reduction in BMR after CPAP predisposes to a positive energy balance, dietary intake and eating behavior had greater impacts on weight change,” the researchers wrote. “These findings highlight the importance of lifestyle modifications combined with CPAP.”

One institution received funding from pharmaceutical and technology companies.


  1. Tachikawa R, Ikeda K, Minami T, et al. Changes in Energy Metabolism After Continuous Positive Airway Pressure for Obstructive Sleep Apnea. Am J Respir Crit Care Med. 2016. doi:10.1164/rccm.201511-2314OC.

This article originally appeared on Endocrinology Advisor