Behavioral and environmental factors may also contrib- ute to the frequent awakenings and the inability to sleep well in the elderly. Poor sleep hygiene, dietary habits, excessive daytime napping,22 and increased nocturia45 may be detrimental to nocturnal sleep. Environmental factors such as noise can affect the quality of sleep,46 particularly because elderly individuals have more N1 and N2 sleep, and may be responsible for causing further arousals and disruption in the elderly. In addition, elderly individuals experience a higher prevalence of medical conditions that make sleep consolidation diffi- cult, including chronic cardiac or pulmonary disease, and any condition associated with chronic discomfort, such as arthritis. Unfortunately, medications taken for the symptoms of these conditions may also promote insom- nia. The prevalence of several sleep disorders also in- creases with aging, including restless legs syndrome and REM behavior disorder. Furthermore, a common sleep
disorder that impairs an elderly individual’s ability to achieve consolidated sleep is sleep-disordered breathing.
SLEEP-DISORDERED BREATHING
Sleep-disordered breathing (SDB) is a broad term that encompasses a range of breathing disorders, from pri- mary snoring through to upper airways resistance syn- drome and obstructive sleep apnea. Less common, but seen primarily in the aging person, is central sleep apnea, which is often associated with CHF.
OBSTRUCTIVE SLEEP APNEA
Obstructive sleep apnea (OSA) is a common syndrome in the middle-aged U.S. population, being present in at least 4% of adult men and 2% of adult women.47 The disorder is characterized by repetitive collapse (apnea) or partial collapse (hypopnea) of the pharyngeal airway during sleep.48–51 These airway obstructions lead to increasingly powerful respiratory efforts until the airway reopens and breathing is restored, often in association with an arousal from sleep (Fig. 2). These transient events also expose the sufferer to intermittent hypoxia and hypercapnia, large swings in intrathoracic pressure, as well as surges in sympathetic activation, all of which have important deleterious consequences.
Effects of Aging on the Pathophysiology of OSA
Aging is known to be a major factor contributing to the risk of OSA, with increases in age associated with apnea prevalence. Ancoli-Israel et al found that 62% of com- munity-dwelling individuals over 60 years of age had a respiratory disturbance index (RDI)