My website and this blog provide what I hope is an useful educational resource for my patients and others, but I know that many patients with snoring and obstructive sleep apnea will never reach it.  As such, I have contributed to two online resources that reach larger audiences.  I am a content author for sleep surgery at, writing the pages for the Pillar Procedure, palate surgery, tongue region (aka hypopharyngeal) surgery, and jaw advancement surgery (maxillomandibular advancement).  In addition, the American Academy of Sleep Medicine recently updated their pages at related to surgical treatment of snoring and obstructive sleep apnea.  The edits I provided on the Surgery Overview and Procedures pages were an attempt to indicate that surgery, although far from perfect, is a treatment option and that a wide variety of surgical options have been developed over the past 10-20 years.

CPAP treatment of sleep apnea may lead to weight gain, not weight loss

The October 2013 issue of the Journal of Clinical Sleep Medicine included a study and editorial relating to a common problem faced by patients with obstructive sleep apnea who may be overweight.  Weight gain is a major risk factor for sleep apnea, and so too does sleep apnea contribute to weight gain.  Many patients with sleep apnea find that they experience fatigue or sleepiness, making it extremely difficult for them to exercise and burn calories.  In addition, obstructive sleep apnea may affect various hormones, such as leptin and ghrelin, that are involved in food intake.  The detailed explanation is more complicated, but on a basic level the increase in calorie intake and decrease in calorie burning can make weight loss challenging.  It has commonly been felt that treatment of sleep apnea, for example with positive airway pressure therapy, will restore energy levels and normalize hormone levels, enabling weight loss to occur.

The study published in the journal comes from the APPLES study, a randomized trial of 6 months of positive airway pressure (CPAP) therapy to treat obstructive sleep apnea.  What this study showed was that those patients who received sham (fake) positive airway pressure had no change in their weight.  In contrast, those who received real CPAP actually had a weight gain.  The amount of weight gain, on average, was low (0.35 kg), but the striking finding was that the more the patients used CPAP, the more weigh they gained–for every increase of 1 hour in usage per night, the additional weight gain was 0.42 kg.  It turns out that other studies (although not all studies) have shown similar findings, but the strength of this study was that it was a large, randomized trial and that it demonstrated such a strong relationship between more CPAP use and more weight gain.  Although this has never been studied for surgery, but my experience is that surgery does not have the same weight gain.  Some patients, for reasons that are not clear, will lose weight right after surgery due to pain in their throat and then can have additional weight loss over time.  I wonder if there is some sort of cycle between sleep apnea and weight gain that is broken, enabling them to lose weight.  Clearly, we need to learn more about the relationship between sleep apnea and body weight.

Patients need accurate information about treatments for snoring and obstructive sleep apnea.  In many cases, relying on our own knowledge base and expectations are sufficient, but everyone–patients and physicians alike–should seek out information and conduct studies to check these expectations against reality.  Challenging accepted wisdom is the reason that I perform research, and I encourage patients and colleagues (surgeons and non-surgeons) to do the same with me.

0 thoughts on “Providing Accurate Information to Patients:,, and Weight Gain Associated with CPAP

  • Yes! Eric, I can’t agree with you more. I think sleep surgery could be the start and key stone to break the vicious cycle of OSA and overweight. People always appreciate me their weight loss after OSA surgery.

  • Hi, I have always been on the stocky side but try and keep as trim as possible with my diet and kept at 78kg ( 5’7” male) , walking the dog daily was my regular exercise but when she passed I did less walking but kept the weight the same. I was eventually diagnosed with Sleep Apnea with 68 episodes an hour and put straight on Cpap. It took a few months to get used to but now I’m averaging 6 per hour . I am now able to walki3 miles a day without any problems, I’m on meds for PAF but dispite the extra exercise I have put on 5kg and gone from a 34 waist to a 36 in 6 months I told the sleep clinic but they said tell my doctor.

    • Jay Mehta says:

      Hi Max, I m having a similar issue. And not sure how to tackle it. I have used the cpap machine for six months now and have put on more than 10kgs, with no major lifestyle changes than before. I don’t know what to do. How did u manage ur situation.? Please share

      • Dr. Kezirian says:

        People can gain or lose weight once they start on CPAP, and there are many potential reasons. There are no easy solutions to weight gain after treatment of obstructive sleep apnea, unfortunately.

  • Max,

    I put on 15 lbs in the first month, 9 of them in the first 9 days, and I did nothing different. I know two more people who have suffered the same, and a lady (now deceased), who went on the CPAP machine, wasn’t eating, and lost no weight at all. I don’t know any more about the deceased lady’s history, but we three, completely independently of each other, because we had no idea the others were even on CPAP machines let alone suffering consequences, had test after test after test to see what was wrong with us, and it turns out that all three of us are healthy–but we’ve packed on this weight very fast.

    The connection seems to be the new machines with the card readers, the electronic ones. One of the people I know had been on a CPAP machine for 15 years (a new one every 5 years) without a problem, switched to the new kind that can monitor your sleep episodes, and put on 15 lbs in a very short time. When I found out, I told him about my experience, he returned his machine and went back to his older model and has lost most of the weight again, without having done anything different.

    The problem is real, with a tangible cause. Just because the experts haven’t put two and two together doesn’t mean it doesn’t exist (my CPAP consultant actually scoffed at me). They just haven’t realised it yet or figured out the science behind it.

    • Dr. Kezirian says:

      This is very interesting and is not something I have ever heard before. I would not expect the newer CPAP machines that send usage information through cellular technology would specifically cause someone to gain weight, so I can certainly understand why someone would have doubted it. It turns out that studies with the older units (whether with cards or without any tracking of usage) showed that, on average, patients were gaining weight when placed on CPAP too. What is most interesting about what you have shared is that someone lost weight after going back to their older model. All I can say is that most of my patients do not gain weight quickly like this when starting with CPAP.

    • Betty Schwartz says:

      I am so glad to find this! I was already overweight and was told the Cpap would help…nope – I have gained almost 25lbs since Jan, with no change in diet etc except to eat LESS and smaller portions…it is causing so many problems…and I dont know what to do. My skinny ENT wont listen…

  • Dear Dr. Kezirian,
    re: water retention
    I was very interested to find this about weight gain. I started CPAP mask (card-reader kind, German brand Löwenstein, I live in Germany) after being diagnosed with apnea (approx. 40 episodes/hr. due to upper nasal obstruction). I almost immediately put on about 4 kg, going from 88-89 to about 93, within just a few weeks, though I had had stable weight through cardio exercise for a few years. But one thing I noticed at the same time – I wasn’t getting up to urinate at night AND didn’t need to go urgently in the morning, the way I had before (sometimes needing to go twice in the night and urgently again in the morning). So I figured the weight gain was water retention. Has anyone looked into whether some of the weight gain in the study could be water retention, by measuring bladder output? I also found some online comments saying CPAP puts air in your gut because you’re swallowing more air at night and I noticed this i myself too. Could this contribute to weight? Maybe a combination of both

    • Dr. Kezirian says:

      Air does not weigh very much, so that would not explain weight gain. Early weight gain could be explained by less urination, but I would expect that to stabilize and not explain continued weight gain that occurs in some patients (and is true for the average weight of people over time).

  • Suzanne winters says:

    I have been on a CPAP for two years and before that i was on nighttime oxygen for mild sleep Apnea. I have made no changes to my diet or exercise but have gone up almost two waist sizes and before that my weight stayed the same for years. Not sure what to do at this point…i used the CPAP all night long until i wake up and have been faithful to use it as directed. I am active and am not obese except for the stomach weight. I have been on every diet you can name for the last year and a half with no results. I never made the connection until i saw this site. Wow! What to do about it???

    • Dr. Kezirian says:

      I do not have an obvious explanation. The limited studies have shown that patients on CPAP tend to gain weight like people do in general. I do not have a great explanation for your unique experience, however.

  • Ive been using cpap for a year now and the same thing has happend to me i am obese. And thort life would get better with proper sleep . But my bmi is much bigger and ive put on 40kg more . Realy not liking it at all

    • Dr. Kezirian says:

      It should not affect the air in a substantial way. CPAP machines create aerosols from any organisms in your nose, throat, or lungs, but someone in the same bedroom as you would be exposed to your organisms anyway.

  • I have been using a CPAP machine regularly for a few years. I normally thatvtime I have had a slow and steady weight fmgain. No other lifestyle changes. The weight gain rate increased during the Covid restrictions. A safety recall on my CPAP machine meant I had to abruptly stop using it. I struggkes a bit the first week, things have settled back to the new normal. Interestingly, I have rapidly lost weight since stopping use of the CPAP machine. Following this weight change on my phone health app. To date 14 lbs lost in 3 weeks . The only change is the use or no use rather of the cpap machine.

    • Dr. Kezirian says:

      That is so interesting. The weight loss off CPAP is not the most common occurrence, although it could be that you were burning calories due to the work of breathing (I was involved in some research along those lines years ago). I am so glad you are losing weight. I am not sure if you will lose enough weight to clear up your obstructive sleep apnea, but we generally want to achieve both weight loss and effective treatment of sleep apnea.

  • I have been on CPAP for a year now. I have gained weight, especially around my abdomen. Lots of bloating and swallowing of air, which gets expelled! During the year I have had times where I stopped using the machine as it seemed to be affecting my teeth. I lost weight whilst off the machine and put it back on when I went back on the machine. I walk most days and have the same diet. I have to use the machine as my saturation level is 77% but moderate apnoea. I am scared of gaining more weight and having other health issues.

    • The general recommendation would be to treat your sleep apnea and then add other strategies for weight loss. Often we see patients who are so exhausted from sleep apnea that they are unable to exercise (and often have an increased appetite). Hopefully good treatment of your sleep apnea can help with that. That being said, your experience is not so unusual, in that people tend to gain weight over time whether or not they are using CPAP to treat their sleep apnea.

  • Sandra Douglas says:

    Hi. I’ve experienced the weight gain too. Everyone told me I’d have heaps of energy and would lose lots of weight after starting CPAP. I’m not at risk of falling asleep behind the wheel anymore, but certainly don’t have the feeling of energy. and have gained a lot of weight in four years. I have severe apnoea.
    Also, another question for discussion. I haven’t had a proper cold or flu since I started on CPAP (4 years) but have felt mildly unwell for about 90% of that time. I have a theory – based on my own observations. I can go to bed with a mostly blocked nose and feeling like I’m going to be really sick with a heavy cold the next day. I use the nose breathing mask and put it on even when I’m feeling that way because I’m so tired and just want to be able to sleep. In the morning, my nose is less blocked but my head and ears feel stuffy. Long story short, I have sore ears, sinusitis, an annoying cough and a slightly sore throat ALL of the time. I’m never sick enough to require treatment (doctor always says they can’t find anything wrong with me) – but I never feel well either. I believe that the air pressure forces the goop out of my nose and into my sinuses thereby creating a constant low-level illness/infection. What are your thoughts on this? I haven’t been able to find a forum with a chat specifically about this.

    • Dr. Kezirian says:

      You may want to see an otolaryngologist to be evaluated. I hope you are not using any of the CPAP cleaning systems like SoClean, as these have a warning in this country about causing inflammation of the breathing passages.

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