Can CPAP Make You Gain Weight?

Scanning through my daily schedule of patients, I noticed Mr. Johnson was on the schedule. I have been following him for over 10 years since diagnosing and prescribing CPAP for his severe obstructive sleep apnea. I last saw him 3 years ago. He was faithful in using his CPAP 100% of the time, and his adherence numbers were perfect, with an average AHI of 1, minimal leaks, and being used 8-9 hours every night. As I entered the exam room and greeted him, I was shocked to see how much weight he had gained (30 pounds) over the past few years.

One of the basic tenets of sleep medicine is that poor sleep leads to weight gain. It naturally follows that sleeping better with CPAP will lead to weight loss. It’s not uncommon to see patients losing weight after sleeping better with CPAP, dental appliances or even after surgery. However, I had seen a few studies over the years showing that a small proportion of people using CPAP may gain some weight, but what I discovered over the past few weeks studying basal metabolic rates and weight loss in relation to CPAP was surprising.

It turns out that overall, CPAP use has been found to increase weight significantly, in proportion to how long you use CPAP. The more hours you use CPAP every night and the more number of years, the higher the amount of cumulative weight gain.

  • Researchers from Harvard and Stanford Universities found that patients randomized to receive CPAP for 6 months gained 0.77 pounds, whereas people on sham CPAP lost 1.5 pounds. Of note, people who more highly compliant (using more than 4 hours/night, at least 4/7 days/week) had higher degrees of weight gain.
  • In another study, overall BMI did not increase in CPAP compliant patients after one year, but women and non-obese subjects did gain significant weight.
  • A Finnish study in 2016 found that CPAP compliant, more obese patients had higher levels of weight gain after 5 years.
  • Lastly, a meta-analysis of randomized only studies analyzed over 3181 patients from 25 studies, finding significant weight increase in compliant CPAP users.

A number of explanations are given as to why CPAP can promote weight gain. The one most reasonable proposal that I saw is that when you have obstructive sleep apnea, your basal metabolic rate (BMR) in higher.  Due to the extra energy demands of having sleep apnea, you burn up more calories. It’s been shown that using CPAP reduces your BMR.  Since dietary intake and your body’s baseline weight thermostat does not change, you’ll end up with positive energy balance, leading to slow weight gain. This concept may also explain weight gain in some children who undergo tonsillectomy for sleep apnea.

Based on this finding, should people with sleep apnea stop using CPAP? Absolutely not. The overall risks of not treating sleep apnea (especially severe cases) far outweigh the potential risk of getting heavier. However, I do think that this potential side effect should to mentioned to all new CPAP users, just like any potential side effects for drugs or surgical procedures.

It’s also important to emphasize the importance of radically changing your dietary habits once you’re able to sleep better with CPAP. 

For those of you currently on CPAP, did you gain any weight? If so, about how many pounds?

Please note: I reserve the right to delete comments that are offensive or off-topic.

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56 thoughts on “Can CPAP Make You Gain Weight?

  1. I’ve also gained weight! About 50+ and more. My BELLY protrudes as well as extra fat(water) deposit. My ankles stay swollen with edema. I can relate to ALL comments. I was also advised about my cholesterol. I want to get off of my machine so badly😭. The pulmonologist had also advised “I feel it’s your machine as well because something isn’t right”. I advised my sleep apnea Dr who said “it may be the settings”. I wake up with a heaviness in my body as it’s full of fluid. Where’s the water going in our body from the machine? I have a Resmed too for women. I can’t lean back when I sit as my body feel full. I can’t sit long as my body feels tight!
    Now I’m being told that I have a condition that’s affecting my kidneys. And now my blood pressure? NEVER had this. I’m praying they do more research as I want to begin sleeping in a recliner and ween myself off. I’m depressed. And I’m mentally tired! Someone needs to listen to us.

  2. Emma, so sorry to hear. It sounds like your additional 50 pounds is likely tipping you over the edge with all your new medical problems. Did your sleep doctor take a look at your CPAP data and make any adjustments? Perhaps consider looking at an alternative to CPAP if you keep gaining weight.

  3. No, they keep giving me the run around unfortunately. I’m waking up with a gurgling sound and I’m frustrated as I feel heavy. They suggested “work on losing weight”. However; I am only able to do so much. I’m 5’1, and carrying over 60 extra pounds on me. I wheeze and it’s challenging to even walk on treadmill or climb a stair. I feel like I’m drowning. I’m mentally exhausted.

  4. Emma,

    If you gain a lot of weight (regardless of the reason) your CPAP pressure may not be high enough. Then you’ll start to have more apneas, which will lead to acid reflux, which can go into your lungs. You can also look at your CPAP data on your own by using free programs such as SleepHQ. Regardless, bug your sleep doctor, or find a new one. Good luck!

  5. I have used my cpap machine for 8 months. I am a compliant user: 7-8 hrs. per night, 7 days per week. I have gained 15 lbs.. There has not been a real change in diet, and I exercise doing water aerobics 5 days per week..

  6. If your daily excercises consist of cardio whether high intensity or low intensity. Your settings may need adjustment quite often. The doctors get frustrated trying to make a decision what should be the correct settings for your cpap machine. They seem to struggle with which way to go. And PHYSICIANS ASSISANTS Do not have the educational knowledge as a Licensed MD has to make decisions with breathing issues. If the settings are not properly set YES it will cause weight gain, high blood pressure, strokes and cardiovascular complications. Also NOTE if you workout exercising consistently there WILL be issues with your breathing and your endurance level. Because of the oxygen level in the bloodstream is working against your aerobics to prevent you from loosing your weight. This is factual information Because I experienced this. They need much more Studies on treating this disease