Dry mouth. High heart rates. Cold feet (and other extremities). Headache. Aerophagia (air in the tummy) while using CPAP. Cramping in the legs and feet. Any or all if this often with an awakening. Amongst the thousands of posts I have read on the Sleep Apnea forums these symptoms appear most often as complaints.
And I have dealt with all of them.
But one I have rarely dealt with is “not being able to get enough air” during the going to sleep process with CPAP. The mystery – CPAP means “Continuous POSITIVE Airway Pressure”. In other words the pressure at the nose (and possibly mouth as well) is higher than the air in general. It must be EASIER to get a normal amount of air. So what causes this inordinate air hunger?
Well ventilatory instability is common in the literature about CPAP. And it has been posited that a separation in the blood supply between the peripheral chemoreceptors (blood gas sensors away from the brain) and central chemoreceptors (blood gas sensors within the brain) might well be the cause of such instability. Indeed this does seem to be the case with me.
I believe this is true because regular neck exercise (and other anti-arthritic strategies) along with the correction of forward head posture makes my tendency to over breath go away apparently by quenching the inordinate air hunger. Anymore if my nose gets stuffy I correct my head posture my breathing normalizes (it was too much) and the nose clears.
But where does all of this likely come from? I think the answer can be found by looking at how the brain stem gets its necessary blood supply.
The brain stem is the major signal distribution center of the brain. The cranial nerves stem from there and many may well play a part with sleep apnea such as:
– airway and salivation control (cranial nerve IX Glossopharyngeal) [apnea and dry mouth]
– tongue control (cranial nerve XII Hypoglossal) [postural apnea]
– Blood pressure, breathing, and aspects of digestion (Vegas Nerve (X)) [Respiratory control system gain. Blood pressure. Heart rates. Gastroesophageal reflux disease (GERD)? Arousal threshold (but probably elsewhere in the brain stem)? Aerophagia (air in the tummy)?]
– Biting and chewing (Trigeminal V). [Teeth Grinding (Bruxism)]
But indeed the central chemoreceptors (blood gas levels sensors) are in the brain stem and failing to supply the brain stem with enough good blood, for me, does indeed result in more breathing and higher heart rates.
The blood supply to the brain stem (basilar artery) is supposed to be redundant with parts of the Circle of Willis, specifically the Posterior Communicating Arteries, being involved. However in half of us the Posterior Communicating Arteries are simply lacking. But the brain stem is simply critical so its main blood supply comes alongside (more or less threaded through and protected by) our neck vertebrae by way of the Vertebral Arteries.
But what if there is inflammation in and around those vertebrae? When I first started my neck exercises I could hear and feel a lot of snapping and popping as I did them. Arthritic inflammation involved?! And when the snapping and popping did occur then there was a feeling of relief. So in my case I do believe inflammation is part of this story.
But often I find that stress brings symptoms even during the daytime. And I do remember many many tension headaches that I did have. And that if I could get the “rock hard” neck muscles to relax the headache would also go away. Perhaps if you compress the vertebra with excessive muscle tension there is less room to transport blood in the vertebral arteries?
But what if you slump the whole vertebral stack forward with forward head posture? Indeed with a consistency that amazes me correction of my forward head posture quenches my tendency to over breath and all of the symptoms associated. I remember on the forums that some had been given a cervical collar and had a better experience with CPAP use. Perhaps the correction of forward head posture (I find myself tending to do this even in bed) is why this was working for them?
So apparently a lack of blood from the Circle of Willis and an intermittently compromised Vertebral Artery path result in breathing and blood pressure increases as the brain stem holds both sensors and the signaling supplies for these systems. Since the rest of the body is likely to be at rest a normal level of carbon dioxide will not be maintained. When carbon dioxide levels get too low circulation especially in the brain diminish. The blood supply problem to the brain stem (and now the rest of the brain) would likely get worse from that. While I did use the term “inordinate air hunger” to indicate what is likely this condition perhaps the body does know best. The thing is we must have blood to the brain stem. That said I have found eucapnic breathing techniques during the daytime and EERS at night using CPAP helpful likely because they deal with the carbon dioxide maintenance issues.
But over all so far the neck exercises along with the other things done to control inflammation and arthritis in my neck along with the correction of forward head posture do seem so far more effective to eliminate breathing instability.
There is one more thing I have recently discovered that seems to help not only the breathing issues but also a tendency to have trouble getting to sleep and staying to sleep as well. I take three heaping teaspoons of activated charcoal in 14 oz of water just before bed time not eating for at least two hours before. I do not know why this works but it is amazingly consistent and since there are no known problems with activated charcoal, well, why not?