Sleep apnea is a far more common — and far more serious — disorder than most people realize. Its actual prevalence is not known with any accuracy because it is grossly under diagnosed. Therefore, we can only estimate from samples in the population. The most often given estimate is that approximately 18,000,000 people in the United States are afflicted with sleep apnea. Only about ten percent of this number is known and diagnosed.
So what is this virtually endemic disorder? Literally, apnea means “without breath,” and this is exactly what it is describing. In sleep apnea, there are periods during which the afflicted individual stops breathing. Normally, during sleep, breathing is relatively smooth and continuous; there is little pause between the end of one breath and the beginning of the next, perhaps two or three seconds during slow, relaxed respiration, but rarely much more than that. Apnea is defined as a pause of ten seconds or more. A pause of ten seconds between breaths during sleep means that something is wrong.
In general terms, there are two sources of possible problems in breathing. One is when something is blocking the airway; the other is when the brain does not get the signal to breath to the muscles. The first, and more common type is called obstructive apnea; the second is called central apnea. Sometimes, these two combine in the same individual, a condition labeled, “mixed-complex.”
Normally, during sleep, the muscles of the tissues that surround the airway relax, lose the tone that they have during wakefulness and the soft tissues surrounding the airway, which include the palate, tongue, epiglottis, tonsils, mucosal lining, and the blood vessels and fat deposits in the neck, can narrow the airway. This phenomenon causes snoring, but when the obstruction becomes complete, or nearly so, it blocks the airway to a degree that interferes with respiration — obstructive apnea. If you are a snorer you probably seen those ‘snoring devices’ or CPAP machines or perhaps even tried one yourself, if you did – it most likely didn’t helped that much or had a big downside to the usage of such device, assessment of my snoring solution chin strap states that it’s a good anti snoring device, but you shouldn’t take it at a face value, what works for most, not necessarily can work for you.
In central apnea, there is a neurological impairment from disease, injury, or drugs that interferes with the mechanism that tells the brain that there is not enough oxygen and it needs to send a signal to the respiratory muscles to take a breath. Many common sedatives, including over the counter sleep aids and alcohol, can suppress the respiratory center to cause, or contribute to, apnea. In both etiologies, the apneic events cause hypoxia, or a lack of oxygen, which sets off a series of physiologic changes that result in partial awakening, allowing the individual to take a breath. In other words, instead of deep and restful sleep, the person with sleep apnea actually is awakening periodically for brief periods of time. Almost always, these periods of wakefulness do not reach a sufficient alertness to be remembered. In other words, the sufferer from sleep apnea usually does not know about the interruption in sleep and believes that he or she has slept soundly all night. Instead of experiencing the full cycle of restful sleep, apnea interrupts this process from five to over thirty times an hour. Five to fifteen apneic events is considered mild; fifteen to thirty, is considered moderate, and over thirty is considered severe. Even the so-called mild apnea, though, can have serious consequences.
We all need to breath, and we all need to sleep. If we do not get enough oxygen to maintain normal homeostatic processes, there are many consequences, none of them good. Similarly, a lack of deep, and particularly, rapid eye movement (REM) sleep, also has potentially serious consequences. The body’s attempt to breath causes a disruptive activation of the sympathetic (fight or flight) nervous system. This, in turn, causes a series of events that are only partially understood, but the net result is an increase in the likelihood of pulmonary hypertension (not good) and cardiac events, including angina (chest pain — also not good) and myocardial infarction (“heart attack,” really, really not good). The degree to which sleep apnea is a risk factor for these serious consequences is not trivial. Depending on the degree of the illness, the risks of some serious event are increased several fold. And I haven’t even mentioned stroke.
OK, those, and more, are possible consequences of the hypoxia (low oxygen) of sleep apnea. The loss of good sleep has its own effects. For one thing, it makes people sleepy. In fact, one of the common ways of measuring the severity of sleep apnea is a scale (Epworth Sleepiness Scale) of how likely the person is to fall asleep during the day while engaged in various activities; as one of these is driving, the seriousness of this problem is apparent. Of course, it is obvious how much chronic fatigue and sleepiness can interfere with everything in life, causing inefficiency, depression, and what looks like attention deficit disorders. Just awakening every morning feeling groggy and tired despite believing that you have had a full night’s sleep is annoying, itself, but feeling bad all day is even worse.