Neil S. Freedman, M.D.
Obstructive sleep apnea is an extremely common, and often underdiagnosed, medical problem affecting up to 4% of the middle aged American population. It is characterized by episodic partial and total obstructions of the upper airway, resulting in a reduction or inability of air to get from the nose and mouth to the lungs during sleep. Disrupted sleep resulting in daytime sleepiness is often the consequence, as the body attempts to normalize its nighttime breathing pattern. Until recently, it was thought that daytime sleepiness with its associated problems of impaired memory and inability to concentrate were the only important symptoms associated with this disease. Several recent studies have demonstrated that obstructive sleep apnea is associated with an increased risk for cardiovascular disease, poorer quality of life, and higher incidence of depression.
Several recent studies have demonstrated that obstructive sleep apnea is an independent risk factor for hypertension (high blood pressure). Individuals with obstructive sleep apnea are up to 3 times more likely to develop hypertension than similar individuals without sleep apnea. It also appears that the risk of developing hypertension increases as the severity of the sleep apnea increases.
The reasons why obstructive sleep apnea increases the risk of hypertension are not totally understood. Typically during sleep, blood pressure and heart rate decrease as the body relaxes. In individuals with sleep apnea, surges of adrenaline are released in response to upper airway obstructions and low oxygen levels. The current thinking is that these surges of adrenaline result in elevations in blood pressure and heart rate through out the night. In some individuals, the elevated nighttime blood pressure translates into elevated blood pressure during both the day and night.
Individuals with sleep apnea are also more likely to perceive their quality of life as being poor. The Sleep Heart Health Study has demonstrated that many patients with sleep apnea have a poorer perceived quality of life when compared to individuals without the disease. Both men and women with more severe sleep apnea have more negative feelings regarding their general health, physical function, social function, and feelings of vitality. The negative quality of life effects appear to be equivalent to individuals with other chronic medical conditions such as hypertension, diabetes and clinical depression.
Finally, some studies have linked untreated sleep apnea to depression and anxiety. However, not all patients with sleep apnea develop psychological symptoms.
The diagnosis and treatment of obstructive sleep apnea needs to be pursued more than ever. Recent research has linked obstructive sleep apnea to a spectrum of symptoms and adverse health outcomes such as an increased risk for cardiovascular disease and poorer quality of life. Future research is ongoing to determine if treating sleep apnea reverses these negative outcomes.