Why would dieting make my AHI increase?

I started APAP back at the end of December. I've responded to it well. From Dec to Memorial Day, my AHI without fail has always been under 1. The day after Memorial Day, I started a low carb diet and also stopped drinking alcohol, something that I would usually drink every day. Since I've cut out the alcohol and went low carb I have lost 7 pounds. (less than 2 weeks, pretty good weight loss). The problem is, since doing this my AHI has risen. It's been anywhere from 1 to 2.5 since then. So either my new food choices, or a lack of alcohol is causing my AHI to be higher than it ever was while using APAP. Does anyone know why this might be? I know that 2.5 isn't a high number, but when I've gone for months with it usually being .25 to .75, it's quite an increase. Thoughts??

Are you sure your mask still fits properly when lying down asleep? It takes very little weight change to make a difference. Maybe using a Padacheek liner would help. If you can use Sleepyhead to see what's going on then you'll have a better idea of how to fix it. There may be other things involved besides the weight.

Mask is still fitting correctly. I'm showing the same leak rate as before. Sleepyhead is not showing me what the problem might be.

What is the event category breakdown of that higher than you want AHI?
How much is each index? You can show it on the SleepyHead detailed report.

When you did drink alcohol did you drink much right before bed?
Do you take any medications of any kind? If so what?

Can you post the SleepyHead report showing the higher AHI along with the usual graphs on the right side...
Events
Pressure
Flow rate
Leak

Let's see if there is any clustering and what the pressure was maybe doing if there is clustering.

If you don't know how to post a screen shot of your detailed report see this thread for examples of how we like to see them
viewtopic/t103468/Need-help-with-screen-shots.html
and this for how to use imgur if you want to use imgur
https://sleep.tnet.com/reference/tips/imgur

I won't be here to comment until later but someone else likely will and I will later when I get home.

Let's see if this works....this is my first time uploading images.

So, this is pretty much what I've been looking like from Dec. to May:


And this is what I've been dealing with since Memorial Day:


Does anyone see anything that jumps out? As far as your question about alcohol, I used to drink after work, so 2-3 glasses of wine, sometime between 4-6 in the afternoon. Usually not right before bed. Oh, I also do not take any medications.

I can't think of anything that would cause that other than a change in your mask fit but I'm not an expert at interpreting the graphs. I'm thinking there may not be a direct relationship otherwise. In my case, I have lost 60 pounds since starting cpap, and both my AHI and leak rate have decreased. I didn't even need to adjust the mask fit as I lost weight.

Hopefully, someone will come along with more expertise in interpreting the graphs.

If the graphs are representative of the two time frames - the first your pressures are going much higher - to 17/18. The second with your better lifestyle, it's only going as high as 14. So to me that just looks like generaly you need less pressure,but that's letting a few more episodes sneak through.
And my wild guess would be something about a bit of weigt loss, or alcohol being a depressant/ relaxant - which I assume may relate to floppier tissues needing higher pressures?
Since your ahi is still good,I don't know hiw concerned you need to be. How do you feel?
(Also not massively experienced at reading graphs!)

Changing the way you eat changes a lot more about your body then just your digestion - read the threads on Keto and diabetes to see how diet affects all parts of you. Stopping alcohol or any other drugs also can make a huge difference and can take weeks for your body to adapt, you may be sleeping deeper and having more REM. Changing my blood pressure medication last month meant 2 weeks of headaches and dizziness as my body adapted.

Losing weight also doesn't mean less apnea events. For about 50% it might mean that but it can also cause an increase in events and need for higher pressures.

In my opinion...and like others, I'm not an expert, the increase seems to be the CAs. You had none before.....With the weight loss, it's possible that you are a little more restless than before. If you are sleeping well and feeling well, I would ignore the CAs and your AHI will be low as it was before.

I agree with Backspinner, et al. An abrupt change in diet could bring about a number of physiological changes which could be the reason behind the changes in CPAP results. You may be suffering from mild alcohol withdrawal as well. Three to four drinks daily is a fair amount to stop abruptly. Pugsy will return with her recommendations, but I think you should consider raising your minimum pressure to maybe something like 12. Ten or 11 is allowing those hypopneas and OA's sneak in and the machine has a long way to go to counter them. My guess would be that as you continue with your new regimen your pressure requirements will stabilize, but it could be higher or lower and, as LSAT says, with a low AHI, priority probably should be given to how you feel rather than to the number itself,

I would suggest raising your minimum to 11 tonight as you spend virtually all your time above that. Then inch it up every few days towards 12. I have few apneas in the first place, but eliminated all the RERAs by raising the minimum just a bit every few days. Keep in mind that it might not be what you are eating at all. I need to raise my pressure in the summer, who knows why. Then come fall, I can drop it again. But weight loss caused for any reason does raise my AHI briefly.

Another case of us being different when it comes to weight loss/weight gain. I've lost close to 30 lbs. in the last several years, and my severe SA (over 50 events) is now moderate SA (sleep study showed 17 events this past Oct.). I was also pre-diabetic. I had a blood work up in January and I'm no longer in the pre-D range. My weight is now what it should be for my height.

My pressure needs remain the same and my AHI remains the same... seldom more than 1.9.

I don't see anything that just stands out screaming "fix me".
It does appear that you increase the minimum from 9 to 10 at some point recently. I would assume that maybe you did that when you started to see the AHI climb a little.
This report above...the CA/central index is less than 1...I had thought maybe the bulk of the AHI increase might be centrals but it looks like it is more equal between CA, OAs and hyponeas. If it was CA/central we might blame it on restlessness or tossing and turning or awake/semi awake breathing.

I don't really have any ideas other than what has already been mentioned. I have never been able to really tell much difference between an AHI of 3.0 and below 1.0 but I know that some people say they can feel the difference so I am not going to dispute it. If you are one of those people then you have to go about it just like you would if the AHI was even higher. More pressure (the minimum baseline) is how to go about it. Try it and see if the AHI lowers and you feel any better or not (if you are feeling badly now).
Just remember that the CAs/centrals can't be fixed with more pressure using your machine so mentally remove any central index from your evaluation process. I know that it's sometimes hard to do but you have to just ignore the centrals since we can't do anything about them...and they don't need to have anything done about them unless your central index was a lot higher than it is now.

As Pugsy alluded to ... how do you feel with the higher AHI? ... can you really tell a difference during the day? ... or are you just concerned over the increased AHI above 1?

I was never able to really tell the difference between an AHI of 0.1 or 3.0 but it is cool to get that long term sub 1.0 AHI ... cuz I've done it before. It's like a game, only it got boring for me after a few years. Also keep in mind that there can be a difference of several long-term average AHI points just between different brand machines (I used to have both ResMed and Respironics APAPs and the ResMed was always 1 to 2 AHI lower). And as others have noted, your sleep behaviour can change over the seasons ... as I recall, Jay had once collected and posted a bunch of correlated seasonal sleep data along with temperature and seasonal solar characteristics.

Anyway, I started my OSA therapy using APAP and a few months afterwards began my weight loss journey. After significant weight loss I also experienced an increase in my sub 1.0 AHI and being a geek of sorts, it bothered me too, even though I didn't really notice an efficacy difference during the day. My first issue was that I began having short duration leaks and so I took care of that problem but then as I continued losing weight, my AHI began to rise again. My friend and CPAP mentor Den (Wulfman) suggested I try CPAP mode and I was hesitant at first. But I did try to narrow my APAP pressure range to only a couple of cm because like yours, my auto pressures were fluctuating up and down alot. Narrowing the pressure range worked for me. In fact, I eventually just set it to CPAP mode and have been using CPAP only for over 6 years now. And I don't keep a close track on my AHI numbers anymore either ... though I will again in a few months when I begin some new experiments with my autonomic nervous system, but I digress.

So regarding your data -- although I'm not as fluent with SleepyHead data charts as Pugsy and others are, the only pattern I do notice is that your pressure jumps around -- and the initial rise on the higher pressure peaks seem to correlate with your event tics. As I recall, the old ResMed APAP machines had a rather aggressive pressure ramp up in their algorithm (unsure of the newer models like yours though). So I dunno, maybe narrowing the setting of your APAP range to 11 for min and 13 for max will help? The other thing to keep in mind is to be patient and not be adjusting pressure every other day. Titrating the optimal pressure can take several months and you should wait a couple of weeks between change of pressure settings should you decide to play around with higher resolution pressure titrations.

I don't know if SleepyHead can plot AHI (or the individual indicies) vs pressure (index on y-axis and pressure on x-axis) -- but if you can, that is a good way to optimize your pressure settings using a global minima optimization approach. When enough data is collected, a U-shape pattern will emerge from the plot such that the base of the U-shaped curve will identify the optimal pressure requirements for the minimal AHI, or OA or H or CA or any combination.

Anyway, hope your weight loss keeps on keeping on.

DreamStalker wrote: And I don't keep a close track on my AHI numbers anymore either ... though I will again in a few months when I begin some new experiments with my autonomic nervous system, but I digress.

Are we talking about breathing rate, heart rate or blood pressure? This sounds interesting.