The Risks of Sleep Apnea

Research has found that individuals who snore or have a sleep disorder called sleep apnea have an increased risk of being pre-diabetic (insulin resistant), of experiencing full-blown type 2 diabetes or cardiovascular disease.

Sleep apnea is an obstructive disorder characterized by repeated episodes of partial or complete cessation of breathing during sleep. These episodes may be classified as obstructive, central or mixed apnea. Obstructive apnea is the absence of airflow despite an effort to breathe. Central apnea is the absence of airflow due to a lack of ventilatory effort. Mixed apnea begins with the central component of no effort to breathe, followed by a lack of airflow despite the fact that the patient is trying to breathe. Apneas or partial cessations of breathing during sleep are considered clinically significant if they last at least 10 seconds, although they usually last for 20 to 30 seconds and can last for more than a minute.

Most episodes of sleep apnea are caused when the throat airway collapses. Muscles relax during sleep and may cause a narrowing of the upper airway during inspiration, hence snoring. This narrowing of the airway also leads to increased respiratory effort and causes the individual to partially awaken. The arousal restores the muscle tone of the upper airways, allowing the individual to fall back to sleep. In sleep apnea, the cycle of sleep and arousal may be repeated throughout the night. Substances that relax muscles, such as alcohol and tranquilizers (benzodiazepines), tend to exacerbate sleep apnea.

Sleep apnea is characterized by snoring, daytime sleepiness, repeated interruptions (partial or complete) of breathing during sleep, arousal from sleep and possibly morning headaches. Long-term sufferers may experience symptoms of fatigue, mood swings, obesity, low sex drive and poor concentration. This condition is more common in overweight or obese individuals and has been linked to high blood pressure, increased risk of heart attack and stroke, diabetes and a pre-diabetic condition called insulin resistance.

The exact association of diabetes and insulin resistance with sleep apnea has not yet been determined, but it may be related to an elevation of stress hormones while sleeping, associated with the disrupted air flow.

Individuals who snore or have sleep apnea may be unaware of their condition. They may deny or minimize their sleep-disordered breathing because of embarrassment. It may be necessary for a listener, such as a family member or spouse, to report any snoring or sleep apnea to the patient or to a health care professional.