Zzzzzz: Sleep apnea is more prevalent at high elevation
March 17, 2014
VAIL — Sleep apnea is a tricky thing.
Symptoms often develop gradually, over a period of months — and even years. And usually, the patient is one of the last to know; often spouses notice loud snoring or even breath holding throughout the night (so singles may have even more difficulty recognizing the condition).
To make matters worse, 20 to 30 years ago, the medical community, and society at large, viewed sleep apnea as more of a joke, said David Everett, owner of Mobile Sleep Services, which performs sleep studies through Vail Valley Medical Center.
"Now, more and more people are just recognizing there is a problem," Everett said, "that sleep apnea is not the joke people used to make fun of — like snoring on TV sitcoms."
Ironically, Everett fell victim to the lack of recognition of his own sleep apnea. For years, he handed out sleep quality questionnaires, only to return home needing a nap because he was "dead to the world," he said. He initially blamed it on a change of schedule — from nightshifts to dayshifts.
Then, one day in 1995, he commented on how loud his 130-pound dog was snoring. His wife responded: "No louder than you," and told him he needed to start practicing what he preached.
Sure enough, when Everett went in for a sleep study, it showed hypopnea.
Types of sleep apnea
Sleep apnea occurs when normal breathing patterns are interrupted while sleeping.
Some people simply have hypopnea, which are drops in the oxygen saturation level measuring four percent below the baseline of a 90 saturation rate for a period of time. If oxygen drops less than four percent but patients still experience arousals, they suffer from respiratory related arousal. Neither of these conditions are actually considered sleep apnea.
Doctors first diagnosed Everett with hypopnea, but over the years, he developed full-blown sleep apnea.
Three types of sleep apnea exist: obstructive, central and mixed. Obstructive is the most common of the three, occurring when a person's tongue falls against the soft palate, in turn causing the soft palate and uvula (the hanging flesh in the back of the throat) to close the airway because they collapse against the back of the throat. It is a mechanical problem, which develops more frequently and often worsens,when people sleep on their backs, reach middle age and beyond or are overweight.
Central sleep apnea involves the brain's signal to the body to inhale. This causes shallow, or long pauses in, breathing. It sometimes alternates with over breathing, to balance levels of carbon dioxide and oxygen in the body.
Mixed sleep apnea is a blend of obstructive and central.
Spouses usually notice one of the first symptoms: episodes of heavy snoring (often early in the night). However, only about half of the 90 million people who snore suffer from sleep apnea, according to the American Sleep Apnea Association.
With obstructive sleep apnea, snoring continues with regular rhythm, often loudening, followed by long periods of silence in which the sleeper doesn't breathe. When the brain registers the lack of oxygen, the person usually lets out a loud snort, gasp or both, and snoring returns.
Though this cycle may sound somewhat dramatic (and loud), the person sleeping often does not register his or her constant "arousals," which Everett defines as short awakenings usually lasting less than one second.
And sometimes people experience the arousals without symptoms of snoring.
"You could have a couple hundred arousals during the night and not know it, and then not feel rested because you're only reaching the light stages of sleep," he said.
People with sleep apnea usually begin to wonder what's wrong as they experience more frequent and more severe days when they feel very tired. They may also notice morning headaches and feelings of restless sleep.
"The longer you have it, the worse the daytime becomes — the more tired you get," Everett said. "You don't feel like getting up and doing anything. … When it gets to a point where a person realizes they're tired, it's more advanced."
As apnea worsens, it tends to cause high blood pressure. When doctors cannot control a patient's blood pressure with medication, it's usually associated with sleep apnea, Everett said.
High elevation and sleep apnea
The pressure at high elevation makes less oxygen available for cells. This causes the body to breathe deeper, faster or both. Everett said it takes an average of three to six months for the body to regulate itself in high elevation and it can take longer. In fact, some people never seem to adjust, he said. As a result, sleep apnea can become a problem.
"It's much more prevalent in high elevation," said Vail Valley Medical Center cardiologist Dr. Robert Orr, adding that many people may reach a 75 to 85 percent oxygen saturation level. "That's very dangerous because the heart needs oxygen. It can lead to the development of atrial fibrillation and ventral tachycardia."
These two conditions compromise heart function as the electrical system of the heart fluctuates, usually by racing but also by skipping heartbeats. Atrial fibrillation can usually be treated and corrected if caught early, but ventricular tachycardia, which involves the lower chambers of the heart, is often fatal without immediate medical intervention.
"The key is to be proactive," Orr said. "A 98 to 90 percent oxygen saturation is not a big deal, but when it (drops) to 90 to 82, it's a big deal."
Testing involves placing non-invasive electrodes on the chin, scalp and face and measuring heart and breathing rates, as well as other indicators, as a patient sleeps.
Treatment ranges from nasal decongestants, abstinence from alcohol before bedtime, sleeping on one's side and weight loss to surgery, depending on the type and severity of sleep apnea. However, supplemental oxygen is the most common treatment.
Pressurized air flows through a flexible tube from machines like CPAPs (continuous positive airway pressure), BiPAP (bi-level positive airway pressure) and VPAP (variable positive airway pressure).
People wear masks over the nose, or nose and mouth, to receive pressurized oxygen, which prevents their airways from collapsing. Oxygen can also be administered through nasal prongs, rather than a mask. Humidification, built within the machines, provides greater comfort in dry climates.
Everett said using oxygen at night is "just like anything" — you have to get used to it.
But he's a lot happier and a lot more energetic now that he paid attention to what he preached and sought treatment for sleep apnea.
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