what are the facts? physiology 101

[nmevan]

hello out there all you smart people and thanks for your input!

During my sleep study I was told that my desaturation oxygen level went down to 68%.
My AHIs were 53 per hour.

my question is this...what harm is it actually doing? I ask this question honestly.

I'm 53, I work-out 2 hours a day, 6 days a week, swimming and mountain biking. My heart is fine. I don't have headaches.
I don't fall asleep during the day and I have never napped.
I do occasionally feel tired during the day from lack of sleep, but I also feel that way after having used the bipap machine.
I also suffer from mild anxiety, which may or may not have anything to do with apnea.

Is it the potential for future heart disease, or other ailments, that has me sleeping the last ten days with a full face mask and auto bipap machine?

What about the brain? When my oxygen level goes down to 68%, does my brain start to die. When I wake myself up, my oxygen level immediately goes back to 98% within seconds.

I am perplexed as to the physiology of the whole thing.

please enlighten me.

thank you!

evan

[Laurie1041]

Hey Evan,

Lots of information regarding the dangers of untreated sleep apnea on the Internet.

I pulled one from National Institutes of Health. My personal summary: Untreated sleep apnea is a killer. I am 50, still run marathons, and run and exercise daily. I am far from overweight, and am conscious of what I eat. Yet, the sad fact remains that my 02 sats drop to 81% and my AHI is 43.9. Physiologically my upper airway collapses when I am sleeping and deprives my body of oxygen and restorative sleep. Why all the big deal? Read on.

I asked my sleep specialist what the consequences were of not treating my OSA. He calmly said that my risk for stroke increases 3 x, that I would be at risk for certain potentially lethal heart arrhythmias (sudden cardiac death), hypertension, and heart attack to name a few. The list actually goes on. . . Evan, please don't wait for one of us to give you a physiology lesson. IMHO, the best thing you can do is to read and read and read. All the best, Laurie

http://www.nhlbi.nih.gov/health/dci/Dis ... hatIs.html

[nmevan]

thank you laurie!

I guess my question is, what is the mechanism for all the potential negative effects?

Does your heart tissue start to deteriorate from a minute of 68% oxygen...53 times an hour? Does it beat harder than it is supposed to and eventually wares down? How does apnea increase ones blood sugar to develop diabetes?
I can understand being tired making one sedentary, or too tired to exercise. But what is the exact science of all these potential disasters?
I'm not saying that they don't exist. I would just like to understand them and the research that was done.
I have read many horror stories, but not the exact science behind it.

I mean no disrespect to anyone on this forum.

evan

[The Guest]

Evan Laurie is absolutely right. Lack of oxygen wreaks havoc on all your organs but especially the brain which uses 20% of the body's oxygen supply. Long term health is very much at risk! I can say that a majority of patients have some sort of arrhythmia when they come into the lab during the first night study. When they have titrations, I am always amazed at how the brain and heart respond to PAP. The brain waves show normal function as opposed to constant arousals and lack of REM sleep in many cases. Also the heartbeat settles down and most of the patients show significant improvement with their arrythmias during the titration. Its amazing everytime and reinforces in me the need for consistent use of PAP therapy.

[Janknitz]

You say you're an athlete, then you are likely to have heard of "cumulative trauma". These are micro tears from stressing and straining muscles, tendons, and joints. Each micro tear, in and of itself, doesn't cause much damage, but cumulatively over time there can be a severe injury that's difficult to treat and recover from. One day the straw breaks the camel's back, and you are too injured to continue.

SA is exactly like that. Sleeping one night with OSA doesn't cause a lot of damage, but it's cumulative damage, and one day it will be enough to show up as a severe consequence of the constant micro trauma you are causing to your body.

Smart people don't wait for that to happen. You may be having no symptoms NOW, but by the time you notice the symptoms, the damage will be very extensive and difficult to overcome.

Be smart. Get treated now, before you regret ignoring it.

[Laurie1041]

Dear Evan,

No disrespect taken and I so apologize if I came off as harsh (certainly did not mean to). As I understand, the lack of 02 puts stress on the circulatory system. You ask a really good question about the exact pathophysiology behind OSA. Let me do some research and see if I can come up with some research articles. I'll get back to you soon! Laurie

[Laurie1041]

Evan,

Here is an excellent interview with Christopher Lettieri, M.D. who discusses the incidence of OSA in the general population, symptomology, statistical relationship between OSA and morbidity and mortality, underlying pathophysiology, and finally treatment options.

I am interested in finding out what you think of this article from Medscape. Laurie

http://www.medscape.com/viewarticle/709202

[nmevan]

hello again, laurie

thanks for the link to the article

I read it, and it indeed has many correlations between sleep apnea and many physically detrimental effects...but it does not get deep into specifics...as to what exactly is happening to the brain or specific organs. The one thing that he does mention is the secretion of cortisol, and that, even I can understand is bad stuff.

I do believe that having untreated apnea is detrimental to ones health...and I will continue to use my machine and hopefully adjust to it eventually.

thank you all for your responses

evan

[BlackSpinner]

Think of this way - everytime your oxygen drops to that 68% your whole body goes into fight mode. Like as if you went from watching tv on the couch to instantly run as fast as you can to do a triathlon - no warmup, no warning and no cool down afterwards- several times each night while someone chokes you.

[JohnBFisher]

Greetings! Blackspinner has it correct. There are two fundamental problems with continued uncontrolled sleep apnea. By being an excellent athlete you appear to have avoided most of the ramifications. However, that does not mean that you have avoided problems. Rather it means you are masking the problems. A friend who runs and is in excellent health recently had to have a stent inserted into one of his arteries in his heart. He had no complications from it. However, his doctors noted that without his excellent exercise routine he would have had a major heart attack.

So, it is with the ongoing damage from low O2 levels. It causes damage that your exercise routine helps mask.

Secondly, though you feel okay, the constant disruptions of your sleep means it is not as restorative as it could be. This disrupts the normal flow of sleep, It robs your body of enough deeper levels of sleep. When you stop breathing your body must arouse itself to a lighter level of sleep. Various neurochemicals are only created during those deeper levels of sleep. Though your exercise routine masks this, deeper levels of sleep are vital to your overall health.

The other problem with all those apneas and desaturation of your blood oxygen levels (and concurent increases in CO2 levels) appears to desensitize the normal breathing mechanisms. Again your exercise helps mask this, but eventually it will lead to ongoing problems.

Hope that provides some food for thought. I applaud you for maintaining your health. I hope you can do so in the future - accompanied by some good sleep.

[robysue]

I'm interested in the OP's question too, but with a slightly different twist.

On my diagnostic sleep study, my O2 never dropped below 91% or 92% and my median 02 was something like 95%. I believe the sleep study summary described the handful of dips O2's as "minor desats associated with apneic events" or some such language. For what it's worth, I only had 14 obstructive apneas during the whole diagnostic sleep study and no "hypopneas with desaturation" and the sleep study listed my AHI as 3.9. But I did have a whopping 78 "hypopneas with arousal" which, near as I can tell, are events that are at least 10 seconds long where the airflow is substantially reduced (by 50%?) even though efforts to breath are present and that trigger an arousal, but these "hypopneas with arousal" do NOT have the tell-tale 3% or 4% drop in O2 levels present in a regular old hypopnea with desaturation. My diagnosis of "moderate OSA" was based on those hypopneas with arousal bumping my RDI (Respiratory distrubance index) up to 23.4 for the night.

So I want to ask some variations on the theme of the OP's original question:

Is the main purpose in treating OSA in a person who does not have any desats associated with their apneas and hypopneas simply to prevent their OSA from deteriorating to the point where they do start desating? Or does OSA without O2 desats in and of itself lead to physical damage? If so, how?

In other words, for folks who are clearly having (at least a few) apneas and (lots of) hypopneic-like episodes but who are not desating, what's the mechanism that causes the real and physical harm to the body in untreated OSA?

Please understand, I'm not looking for a way out of CPAP: I've been compliant right from the start even though I still feel worse on CPAP than I ever did before starting and I'm now 6 weeks into treatment. I keep hoping that one day I will have my energy back and that my mind will no longer be in what feels like a CPAP-induced mental fog every day. But for now, I'm simply trying to understand what actually was happening to my body before CPAP and what is happening to my body now that I'm using CPAP.

[chunkyfrog]

Evan; you are extremely lucky to have been diagnosed so early--before much damage has been done.
Now it is up to you to take care of your apnea--before it wreaks havoc on your circulatory system, your internal organs and your brain.
Untreated; you face serious health consequences; as many here have already suffered.
Some of this damage is irreversible. The ball is in your court. Please be well--for your loved ones and yourself.

[robysue]

chunkfrog,

Intellectually I know that I'm lucky to have been diagnosed before any seeming damage to my body has been done.

Intellectually I also understand that if I were to simply opt out of treating it, I'd be back here in some number of years (maybe a decade or maybe only a couple of years) needing to treat my apnea AFTER I start to suffer from the long list of symptoms that clearly indicate permanent damage has been done.

And at this point my intellectual brain is in charge: I really have been 100% compliant right from the start: If I'm in bed (for the night or for a nap) my mask is on and the machine is running.

And I don't intend on stopping CPAP any time soon. But on the other hand, my husband's getting plenty tired of my snarling at him all the time now simply because I am now clearly much more sleep deprived with CPAP than I ever was without it and I am clearly suffering from my current sleep deprived state in multiple ways that I was not suffering from before CPAP. Most notably my temper is much, much shorter now than it was before CPAP, I have no sense of humor any more, and I am now physically too tired and exhausted to do much of anything except my job and the work needed to deal with the CPAP every night and morning. Prior to CPAP I was not particularly short tempered, I did have a decent sense of humor, and I had plenty of energy for getting through the day at work and still had energy to do things with and for the family. So my adjustment to CPAP so far has been as rough on my loved ones as it has been on me.

But my questions for now are simply these:

Since I currently am NOT having desaturations with my apneas and "hypopneas with arousal", is the OSA actually doing damage NOW to my body? And if so, what's the mechanism? How do the arousals themselves cause the damage?

Or is my CPAP treatment serving a prophylactic role in that its sole purpose is to keep my OSA from getting to the point where I would start destating and then start having physical damage caused by the desats?

If my CPAP treatment is largely prophylactic, I can live with that: I just want to know that that's what its role really is.

And if my CPAP is largely prophylactic, then that might explain why I'm feeling worse instead of better: If my CPAP treatment is primarily to prevent nasty things from happening to my body and mind in the future, there's no good reason to expect the treatment to make much difference in how I feel in the present. As a prophylacic treatment, CPAP should keep me feeling as good as I felt before the OSA diagnosis for many, many years to come since, as a prophylatic, it will prevent me from ever developing the nasty physical damage and symptoms of more advanced cases of OSA. But since there are noticible and irritating side effects of the treatment, it's not a surprise that I'd notice them more if my CPAP treatment is not likely to make any difference in how I feel in the present because I don't yet have any physical damage to cause the (significant) symptoms that CPAP significantly improves in the many OSA sufferers who are unlucky enough to have serious physical damage done to their bodies by OSA before being diagnosed with OSA.

[Muse-Inc]

...Is the main purpose in treating OSA in a person who does not have any desats associated with their apneas and hypopneas simply to prevent their OSA from deteriorating to the point where they do start desating? Or does OSA without O2 desats in and of itself lead to physical damage? If so, how?

In other words, for folks who are clearly having (at least a few) apneas and (lots of) hypopneic-like episodes but who are not desating, what's the mechanism that causes the real and physical harm to the body in untreated OSA?...But for now, I'm simply trying to understand what actually was happening to my body before CPAP and what is happening to my body now that I'm using CPAP.

PSG: AHI=62, all hypops, 1.15 mins of Stage 3 sleep & no REM all Stages 1 & 2, no abnormal heart rhythms, no limb movements, desatted to 83% (not all that low ). But, at the time my BP had risen to 215/110 from my family's usual low BP something like 65-70/60. I pee'd typically 8-10 times/night. I'm sure I had brain lesions like all severe apneics who've had brain scans at diagnosis as I had the typical cognitive & memory deficits of many with untreated severe apnea. What's the damage with untreated hypops? Night-time oxygen starvation causes the brain to go nuts and send out a super-powerful fight or flight signal that jacks up your BP to increase BP & pulse & respiration rate -- we severe apneics 'sleep' thru this call to arms most of the time until its gets really, really, really extreme. When the BP get really high, the body goes on alert and says reduce BP by dropping blood volume, ie, create urine, hence the night-time peeing called nocturia. If this goes on long enough, the hypertension at night continues into the daytime and eventually results in drug-resistant hypertension 24 hrs/day. It's drug-resistant because the cause is the night-time oxygen deprivations, the off & on hypoxic episodes from in my case shallow breathing, very shallow, called hypopneas. You can even have these during the daytime. If a doctor happens to prescribe angiotension receptor blockers, then the apnea might not be detected for some time as this is the best class of drugs to manage the oxygen-starvation caused hypertension we apneics experience. Meanwhile, the repeated fight of flight messages make a chemical stew of your blood chemicals and the levels begin to go haywire as the body begins to adapt to living with no-enough oxygen while asleep. The brain eventually won't let us sleep deeply as our breathing naturally slows as we sleep deeply and we already have problems with shallow breathing...eventually we don't have any deep, restful sleep and we stop dreaming except in fragments at best. The heart is eventually over-taxed and damaged from the nightly episodes of oxygen starvation. And, the vascular damage attributed to diabetes...uh uh, it's from apnea -- they did a scrapping of the lining of the arteries of diabetics, diabetics with apnea, and apneics...the damage is linked to apnea not with diabetes. Another effect of 5 yrs of untreated apnea...ta da, are ya ready for it...diabetes. And most type 2 diabetics have apnea. Apparently apnea activates diabetes genes...lovely huh?

[Mammal]

Muse,

Thank you for filling in the gaps in my knowledge. In a general way, I knew the basics of what you described, but not in that detail. I have been 100% compliant since day 1, but now I am going to be 1000% compliant!