The effect of presleep anxiety on respiratory instability during sleep

Abstract

Ventilation falls at sleep onset as a consequence of the inactivation of a wakefulness specific input to the respiratory system. The magnitude of the difference in ventilation between wakefulness and sleep is thought to be positively related to respiratory instability during subsequent sleep. It is also known that psychological arousal can result in hyperventilation. The present paper evaluates the hypothesis that the mechanism producing hyperventilation to arousing stimuli during wakefulness is the same as that inactivated at sleep onset It was predicted that the magnitude of the fall in ventilation and subsequent respiratory instability would be a function of the subject's presleep arousal level. To test the prediction, presleep cognitive arousal was manipulated in Experiment 1, while anxiety level was varied in Experiment Z Neither manipulation produced hyperventilation immediately before sleep, or affected the magnitude of the fall in ventilation at sleep onset. Experiment 3 reassessed the hypothesis in subjects selected as hyperventilators on the basis of an anxiety-provoking task presented in the afternoon. However, while subjects hyperventilated in response to the manipulation in the afternoon, they did not do so immediately before sleep. It was concluded that the respiratory response to anxiety-provoking situations is inhibited in preparation for sleep and that the subsequent fall in ventilation at sleep onset is a consequence of an independent mechanism.