ABSTRACT
The major physiological consequences of sleep apnea include (excessive) daytime sleepiness and effects on the cardiovascular system. Daytime sleepiness is a typical complaint of sleep apnea patients and has generally been thought to result from the repeated arousals during nighttime sleep that are necessary to breathe, i.e., nighttime sleep of apneic patients is fragmented and not refreshing. Although the daytime sleepiness can occur at any time of the day, it most commonly occurs during the afternoon or early evening. The observation that naps do not usually provide relief from feelings of daytime sleepiness suggests that factors other than nighttime sleep fragmentation may be involved. In this chapter, we first briefly review data indicating that cytokines are involved in sleep regulation. We then present evidence that some effects of sleep apnea may include alterations in cytokine profiles. Finally, we conclude by speculating that alterations in cytokine concentrations/profiles may be one of several causal factors of the daytime sleepiness typically associated with sleep apnea.
