What's the rationale behind AHI < 5?

[Marcman]

I've always been curious why an AHI less than 5 seems to be considered "good enough"?

Because I was just looking at my data for last night and I had an AHI of 2.7 and while that is a lot lower than what I had in my pre-CPAP initial sleep study, it is still 2.7 events per hour and I would think that means that I am still being awoken from deep sleep. When I look at my detailed graphs, I don't know if I've ever seen an event-free stretch of sleep longer than an hour. Doesn't that mean that sleep phases are likely getting cut short?

What is the motivation behind the "less than 5" guideline? Is it just unrealistic/impractical to eliminate all apneas and hypopneas? Or is it because our machines tend to pick up a certain number of false events? Or do normal people have apneas and hypopneas just like us?

Just curious.

[Alshain]

Mostly because the machine will log events that are not real. This is especially true for centrals, the detection system pulses air to see if your having a central, but many will unknowingly hold their breath while switching their position which can cause false centrals to be recorded. I'm not sure of all the conditions that cause a false recording, but this is how it was explained to me.

Furthermore, having a few apneas a night will not impact your quality of life, the oxygen levels in your blood, or the effects of sleep apnea on the heart significantly, even if they are real apneas. Sometimes trying too hard to get a perfect score can make the situation worse, so it's generally good not to mess with it too much if your less than 5.

[Pugsy]

Or do normal people have apneas and hypopneas just like us?

Normal people can have them also. They just don't have so many of them like we do.

[ameriken]

What is the motivation behind the "less than 5" guideline?

I think it's the other way around...the motivation is that if have "more than 5" then you have an issue that is beyond normal and needs to be dealt with and getting back to "less than 5" is getting back to normal.

[avi123]

It's similar to saying that you should have Cholestrol below 200, blood pressure below 120/60 and BMI below 18.
Regardless of age and underlying medical conditions, which imo, is stupid.

In this forum I have read posters' posts who show AHIs above 20, while CPAPing, and feel OK, and on the other hand there are posters with AHIs below 2 who feel sicker than dogs.

[chunkyfrog]

Of course, my AHI of only 13 had a profound effect on my health and well-being.
After 16 months on CPAP, I am so much more fit, that all my medical professionals have commented on it.
Everyone is different. Some people may be able to tolerate an AHI (untreated ) of 20,
but I would never want to share the highway with such a person.

[archangle]

It's just a "rule of thumb." It's convenient to have a number to use as a guideline.

Insurance payment rules also figure into it. Many policies require AHI > 5 to get coverage.

Remember that AHI isn't everything. One 3 minute apnea per hour is a lot worse than twenty 10 second apenas per hour, even though AHI will say otherwise. That's one reason it's so good that modern machines record waveforms.

[dsm]

I have wondered if the target of 5 AHI was achieved by a group of medical researchers down at the pub on a Friday night.

I can see such a group arguing over what the # should be then settling it with a game of darts (or whatever)

DSM