Why Did My AHI Score Go Up?

Checking Your AHI score I’ve been on CPAP therapy now for over two months and as I’ve mentioned elsewhere, my AHI Score went from the mid-70s during my sleep study to somewhere in the five to seven range while using my CPAP machine.  For the second time though in the last month I’ve had a really strange anomaly – my AHI score jumped up to over 13. The first time it happened my score went from 6.4 to 15.3 in one night and I was a little bit concerned.  Was I going to be tired that day?  Is this the new normal for me now? Then the other night, I came home from work and checked my Icon+ CPAP Machine and it showed that the previous night’s AHI was 13.1.  I checked the leak numbers and my SensAwake figure and nothing seemed amiss.  I just rolled the shoulders and carried on. The most important thing that I’ve discovered with trying to overcome my obstructive sleep apnea is to focus on how I feel rather than the statistics.  When I first went got my CPAP machine I would worry about the results every single day, hoping that my “numbers were good”.  The truth of the matter is, I felt great, I wasn’t tired, no more inadvertent naps or falling asleep in front of the TV at 7:30 at night.

Checking Your Sleep Data

One of the idiosyncrasies of my Icon+ machine is that it doesn’t write or update your data on the USB stick until noon each day.  That makes some sense when you think about it because Fisher and Paykel are trying to ensure that if you have multiple sleep sessions during a 24 hour period, they capture the entire day and are able to calculate the figures for the full 24 hour period.  On the other hand, that means I can’t check my sleep data before I go to work or when I first wake up in the morning. And you know what?  I actually like that.  I really think that if I had the ability to roll over in the morning and bring up my AHI numbers on the display, I’d be thinking about it all day and I think it would have some kind of impact on the way I felt that day.  Without knowing the numbers, I just get on with it and check when I get home from work. I suppose I still haven’t answered the question about why the numbers on a couple of occasions suddenly spike up?  Well, I have a pet theory about this.

The SensAwake Feature

I think the spike is down to the “auto” algorithms in the machine.  The SensAwake features and the auto-titration elements of the CPAP machine adjust the flow of air based on “feedback” from your breathing patterns.  My feeling is that maybe I’m just sleeping more lightly or something and am having more hypopneas rather than apneas and therefore the numbers might be elevated.  This potentially could wreak havoc on the machine’s algorithms which try and make the airflow comfortable by making small adjustments rather than massive increases in titration when you start having events. I’m going to look at the data a bit more closely this week.  The good folks at Fisher & Paykel don’t make their InfoSmart software available directly to patients, so I’m not able to see the detailed sleep data easily.  I’ll probably spend an hour this week looking at the open source, SleepyHead software and see what that can tell me.  Hopefully, some more detailed data will either confirm my theory or give me more insights.  Either way, I’m not too concerned about it because like I said, I feel so much better now that my odd AHI scores are just a curiosity piece for me more than anything else.

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As a long term Sleep Apnea sufferer, Sean has researched the topic extensively and tried several different therapies and lifestyle changes with varying degrees of success. His efforts now are focused on helping people get diagnosed early and begin treating their Sleep Apnea to avoid long-term health impacts.

24 thoughts on “Why Did My AHI Score Go Up?”

  1. I perfectly understand how the poster feels. I had the same experience. After being diagnosed with severe APNEA, I was given a ResMed9, Autopap, and my numbers stayed for about a year in the 1.7 to 3.9 or even 4.0 range. Then suddenly a few days back they shot up to 22, 66, and then back to 15, 12.3, and so on. This sudden spike in the numbers is worrisome and I have no (physical) explanation for it.

    I looked the factory set and my top pressure is 16m which I think is adequate to control most Apneas.

    The sudden spike (I’m guessing) could have been the product of two things. One, the use of Viagra, which is known to cause an elevation, and, two, my sleeping on my back due to stuffy nose.

    But the double digits now, when neither is operative, is a puzzle.

    Any ideas?

    • Hi Patrice,

      When I get a cold, my AHI numbers shoot up quite considerably. From the low single digits (3 – 4.5) to sometimes north of 10.

      After a few days when the cold or flu settles down and my numbers return to normal. I just assume phlegm and such get into my throat and cause breathing problems.

      I have also noticed that when I am sick, since being on CPAP, I get better more quickly. I attribute this to better sleep and deeper breathing at night.

  2. I use a ResMed10 for the past 3 months having had a ResMed9 for 3 years and for the recent 3 months my AHI has been less than 1 sometimes hitting 0.0. Lately my numbers have gone erratic; 5.6, 12.5,19,7,19.5,3 and last night 20.1. I am sheltering in place at 7,100 feet but I have had low AHI in the past at this altitude.I just received a new mask, cushion, hose and it makes no difference. I upped my pressure from 8 to 10 to 9 to 11 trying to change the numbers. It is some comfort to hear (see) others have similar problems. I do feel fine and doubt that I stop breathing 20 times an hour.

    • I think it depends.

      The machines are pretty accurate, so it’s likely some kind of equipment issue.

      Trial and error until you figure it out.

    • I always suggest the first thing people with CPAP should do is “not worry” when their numbers change.

      Just methodically think about what’s changed in your sleep routine – are you staying up later, are you stressed, are you eating dinner at a different time?

      Also, consider any changes to your equipment – if you replaced or adjusted something, then that might be a problem.

      The last thing is, carefully consider how you feel. If you wake up the next morning alter and refreshed, but the numbers say you had a high AHI, just make a mental note and move on.

    • I think it’s a case of trial and error.

      If you’re feeling fine when you wake up, that’s a good start, that’s the point of the therapy, not necessarily the AHI score – that’s just a data point.

      Have your sleep technician look at what pressure your machine is producing at the time when your AHI spikes – it might just be that the machine isn’t ramping up (if it’s Auto) fast enough.

  3. I’m responding to this website due to my concern! After consistent readings of 1.9 to 3.5, I came in with an 18.0 last night. This has happened on a few occasions over the past few years and episodes are increasing. One personal theory is due to my ‘always present’ knee pain and sleeping uncomfortably. I’m scheduled for knee replacement this month. In order to compensate for the pain, I find myself changing positions throughout the night Might that be a possibility?

    • Could be secondary pain impacting the quality of your sleep.

      I’d suggest you not worry about random spikes until they become consistent AND you start to feel tired or sluggish when you wake up.

      The number one indicator that CPAP therapy isn’t working properly is that you wake up not feeling like you slept well, your AHI then is supporting data for that.

  4. One suggestion: try not to sleep on your back or stomach. The most preferred way of sleeping while using a cpap is on your right side… then on your left side. My numbers are already better when I purposely sleep on my side. However when I find myself sleeping on my back my numbers become extremely high. Of course avoid alcohol and avoid eating within 4 hours of going to bed.

    • Your machine, if it’s an auto, should compensate for that by ramping up the pressure.

      That’s the advantage of modern CPAP machines – they are intelligent and reactive to what’s happening in real-time. That’s literally the point of them collecting all that data.

      If you sleep on your side or stomach and your AHI spikes, then the CPAP machine should increase the pressure substantially to re-establish clear airways. That’s its job.

      If your soft palette is so flabby that it can’t be prized open by maximum pressure, then you probably should consider surgical options.

  5. I have recently had the same anomalous spikes and have been using ResMed since the Phillips disaster. With a less severe sleep apnea diagnosis of 28 I’ve consistently been below 5 for the past 5 years and recently a low of 0.2 twice after extreme exercise.

    Last two nights 12 to 13 ahi with a leak of 10 which is well below normal. I recently started back sleeping due to a hip injury which helps the hip but use a contoured snore pillow which until the spikes was perfect.

    As an Olympic class snorer I use a chin strap and as I’m due for a new mask, hose pillow etc will try that.

    • You could also consider tightening your mask.

      Back sleeping makes it loose, so tightening it up might leave imprints on your face in the morning but you’ll sleep well.

  6. my numbers raised a few times but my doctor said as long as it averages stay in the 8’srange your ok. Why can’t they go to 1 or zero. Maybe someone could answer if it is good or bad.

    • Good question.

      “Normal” is up to an AHI of about 5 consistently over the course of a night, so 0 or 1 is anamolous.

      The 8’s are a good number – from what I’ve read and experienced over the last decade, anything below 15 usually means you wake up feeling pretty good and under 10, you’re getting a very good night’s sleep for the most part.

      The thing to do is remember that AHI numbers on your machine are data points. If you sleep well, feel good in the morning, and aren’t tired or drowsy the next day, then that’s the point of the therapy.

      And the converse is also true – if your AHI is 2 but you wake up feeling like rubbish and are struggling to stay awake during the day, then you need to figure that out.

      Focus on how you feel and use the data to guide you when you don’t feel good.

  7. Is sleeping on your back with the CPAP good, or should I try to stay on my side. Some nights when I roll on my back it feels good to sleep that way, but I’ll wake up and go on my back.


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