Got AHI below 1, Still only sleep ~4-5 Hours a Night

Hey everyone,

(Quick note: I used ChatGPT to help clean up the grammar and layout here, but all the data, timeline, and numbers are 100% accurate.)

Hoping someone here has dealt with this and figured out a fix, because I'm hitting a wall. My sleep issues started back in December 2024. I was officially diagnosed with sleep apnea in June of this year and have been on machine therapy for exactly 2 months now. I initially started out on APAP while dialing in my titration, but at the beginning of this month my doctor switched me over to fixed CPAP at 11 cmH2O after finding my ideal pressure.

The problem is the early morning awakenings. I go to bed around 9:30–10:00 PM, sleep solid until about 3:00–3:30 AM (roughly 5 hours), and then my brain just turns completely on. Falling back asleep is impossible.

For a while I was taking low-dose quetiapine off-label in the middle of the night just to knock myself out for a few more hours, but I've been totally off that for weeks now. The 4–5 hour wall remains unchanged.

Here is my current setup and data:

* **Machine:** ResMed AirSense 10 AutoSet (fixed CPAP at 11.0 cmH2O, EPR 3 / EPAP 8.0)
* **Mask:** AirFit F40 + mouth tape
* **Numbers:** AHI is consistently under 1.0 (last night was 0.82 with 0.16 OA, 0.33 CA, 0.33 H). Median leak is 7.2 L/min, under 1% time over redline. FL and snore medians are flat at 0.00.

When I look at OSCAR, the first few hours of deep sleep look super clean. Around the 4–5 hour mark, when REM hits and breathing gets more erratic, I just pop wide awake. No major leak spikes or obstructive clusters right beforehand that explain it.

A couple questions for the veteran OSCAR readers:

1. If your numbers are clinically "clean" (AHI < 1 on fixed CPAP) but you're stuck at 5 hours, was it an airway issue the machine missed (like subtle flow limitations/RERAs), or did it turn out to be sleep maintenance insomnia / circadian?
2. Anything specific in the flow rate waveform I should zoom in on right before the wake-up?

Posting my OSCAR daily summary and flow rate graphs below. Appreciate any feedback or ideas on what to try next.

You can resize the graphs so that you can get the flow limitations included in one screen shot and no need to do separately.

Are you having any nasal congestion at night? Sometimes FLs will be increased because of nasal issues and cpap can't fix those. You would need to address the nasal congestion in the more traditional ways to fix that problem if you are having nasal congestion.

Did you have this sleep pattern of waking after 4 or 5 hours sleep with the inability to fall back to sleep prior to starting cpap? Maybe this sleep issue is unrelated to the apnea issue.

Did you know that it's normal to wake after a REM cycle and before that 4 or 5 hour time frame you probably had 2 or 3 other REM cycles that you don't/or didn't wake up after?
Obviously not being able to go back to sleep is unwanted in your case.
It's called sleep maintenance insomnia and it's a real bitch. Believe me I suffer from it myself but it's related to other health issues and nothing to do with apnea issue.
It's really hard sometimes to figure out the why and even then not always so easy to fix. Been there and done that myself.

PikaRaichu wrote: ↑

Sun Aug 16, 2026 5:14 am

The problem is the early morning awakenings. I go to bed around 9:30–10:00 PM, sleep solid until about 3:00–3:30 AM (roughly 5 hours), and then my brain just turns completely on. Falling back asleep is impossible.

PikaRaichu wrote: ↑

Sun Aug 16, 2026 5:14 am

When I look at OSCAR, the first few hours of deep sleep look super clean. Around the 4–5 hour mark, when REM hits and breathing gets more erratic, I just pop wide awake. No major leak spikes or obstructive clusters right beforehand that explain it.

Appreciate any feedback or ideas on what to try next.

Welcome to the club. See my comments and a couple external links to discussion of sleep maintenance insomnia in this recent thread on a similar topic.

Pugsy wrote: ↑

Sun Aug 16, 2026 8:26 am

You can resize the graphs so that you can get the flow limitations included in one screen shot and no need to do separately.

Are you having any nasal congestion at night? Sometimes FLs will be increased because of nasal issues and cpap can't fix those. You would need to address the nasal congestion in the more traditional ways to fix that problem if you are having nasal congestion.

Did you have this sleep pattern of waking after 4 or 5 hours sleep with the inability to fall back to sleep prior to starting cpap? Maybe this sleep issue is unrelated to the apnea issue.

Did you know that it's normal to wake after a REM cycle and before that 4 or 5 hour time frame you probably had 2 or 3 other REM cycles that you don't/or didn't wake up after?
Obviously not being able to go back to sleep is unwanted in your case.
It's called sleep maintenance insomnia and it's a real bitch. Believe me I suffer from it myself but it's related to other health issues and nothing to do with apnea issue.
It's really hard sometimes to figure out the why and even then not always so easy to fix. Been there and done that myself.

Hi Pugsy,

I started having these wake up issues back in December 2024, so yes prior to starting CPAP.

I actually fought like hell with my partner not to go to a sleep specialist because I didn't want to be believe I had SA. I exhausted all options before: ENT, Physio, Mental health, Neurologist, etc.

Regarding the nasal congestion, I visited an ENT to check my nasalcavities, and also several hours with a respiratory physiotherapist who gave me a great nasal clearing routine at night so I’m good there.

Now that I have gotten the Apneas under control, I wanted to reach out to you all for advice. I will look into SMI, that you mentioned. Thank you

Sleepzilla wrote: ↑

Sun Aug 16, 2026 9:43 am

PikaRaichu wrote: ↑

Sun Aug 16, 2026 5:14 am

The problem is the early morning awakenings. I go to bed around 9:30–10:00 PM, sleep solid until about 3:00–3:30 AM (roughly 5 hours), and then my brain just turns completely on. Falling back asleep is impossible.

PikaRaichu wrote: ↑

Sun Aug 16, 2026 5:14 am

When I look at OSCAR, the first few hours of deep sleep look super clean. Around the 4–5 hour mark, when REM hits and breathing gets more erratic, I just pop wide awake. No major leak spikes or obstructive clusters right beforehand that explain it.

Appreciate any feedback or ideas on what to try next.

Welcome to the club. See my comments and a couple external links to discussion of sleep maintenance insomnia in this recent thread on a similar topic.

Hello! thanks for the links. I checked them out, and it's definitely not an easy problem to fix.
Wouldn't wish this on my worst enemy lol.

Apart fom the "awakening" issue....how do you actually feel since you began sleep therapy?

Has there been a change to how you feel and do the stats you posted, show an improvement from your test results?

FWIW...I usually have a more conscious period (semi awake) every night around about similar to your times (I think...without checking)...but I always go back to sleep until alarm time.
It does not worry me and I continue to get AHI results that satisfy me despite them being nothing as good as your. 0.82AHI.
Key to me is how I feel during the subsequent day...and that is ...GREAT ( no apnoea effects like drowsinesss, fog or dropping asleep).

BTW...I use certain relaxation and mind techniques to help sleep.

Craig H wrote: ↑

Wed Aug 19, 2026 6:12 pm

Apart fom the "awakening" issue....how do you actually feel since you began sleep therapy?

Has there been a change to how you feel and do the stats you posted, show an improvement from your test results?

FWIW...I usually have a more conscious period (semi awake) every night around about similar to your times (I think...without checking)...but I always go back to sleep until alarm time.
It does not worry me and I continue to get AHI results that satisfy me despite them being nothing as good as your. 0.82AHI.
Key to me is how I feel during the subsequent day...and that is ...GREAT ( no apnoea effects like drowsinesss, fog or dropping asleep).

BTW...I use certain relaxation and mind techniques to help sleep.

I feel slightly better, but not as good as someone who can sleep a full 8 hours.
My AHI during my study was 17, so definitely an improvement.
I do not feel GREAT at all, just slightly better than I did without using CPAP. I still can't exercise and be as active as I'd like to be so that is why I’m here to look for answers.