Research: CPAP and Weight loss

Research DefinitionResearch Definition

Will CPAP Use help with Weight Loss?

CPAP Device

CPAP Device

Obesity is an important risk factor for the development of obstructive sleep apnea (OSA) and we know that weight loss can reduce apnea severity or even lead to a resolution in some patients.  Obstructive sleep apnea (OSA) is a chronic condition that is characterized by repeated episodes of airway collapse while breathing.  These collapses are often associated with snoring and intermittent low levels of oxygen or hypoxia.  The results are inadequate sleep and/or poor quality sleep that results in an elevated risk of disease of which one is obesity.  OSA is commonly found in association with metabolic syndrome, obesity, insulin resistance, hypertension, and cardiovascular disease.  

Weight gain is caused by a very complex issue.  Obesity increases a person’s risk of developing OSA with, but will the treatment of OSA cause weight loss.  We know that weight gain is caused by a complex interaction of hormones that result in weight gain or weight loss.  Some of these hormones are increased by obstructive sleep apnea.  These inflammatory cause or source cytokines are believed to be the cause of chronic diseases associated with OSA.   The primary treatment for OSA is the use of a machine called a continuous positive airway pressure device or CPAP.  It makes sense that if we reduce these same compounds by treating OSA that weight loss would occur.  The problem is that limited research has been done to look at an answer to this very question.  

In 2017, a study was done to investigate this question by performing a chart review to look at 78 patients[1].  The group was divided and one group was treated with CPAP and the other was a control which did not receive treatment by CPAP.   The goal was to investigate if there was a positive effect on weight loss when OSA was controlled.    The researchers used body weight as a marker for success in either of the two groups.  The researchers failed to find a significant difference between the two groups.

In another study, CPAP was found to increase body weight when compared to a patient without CPAP[2].  We know that obstructive sleep apnea is associated with increased body weight.  The problem with this study is that they did not measure the effectiveness of the treatment or determine compliance.  CPAP is unlikely to cause weight gain and is likely that the OSA is the cause and the OSA is incompletely treated.  

The bottom line:  CPAP may not have a direct effect on weight loss and may even be associated with weight gain.  However, the theory that CPAP would reduce weight gain or increase weight loss is based on sound scientific theory.  Patient compliance could be a factor in the study.  CPAP compliance tends to be low and it is difficult to determine who is being compliant and who isn’t.  More research is needed to look whether maximally treated OSA with CPAP lowers weight gain or increases weight loss.  I would recommend that all patients with OSA consider treatment with CPAP or an oral device.  Even if it does not promote weight loss, and will improve sleep and help lower your risk of other sleep apnea related illnesses.


M. Mahendran et al., “The Effect of Compliant CPAP Use on Weight Loss,” C, vol. 152, no. 4, p. A1082, Oct. 2017 [Online]. Available: 10.1016/j.chest.2017.08.1116″ target=”_blank” rel=”noopener noreferrer”>
R. Redenius, C. Murphy, E. O’Neill, M. Al-Hamwi, and S. Zallek, “Does CPAP Lead to Change in BMI?,” J Clin Sleep Med, vol. 4, no. 3, pp. 205–209, Jun. 2008. [PMC]
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About the Author

I am a family physician who has served in the US Army. In 2016, I found myself overweight, out of shape, and unhealthy, so I made a change to improve my health. This blog is the chronology of my path to better health and what I have learned along the way.

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