Brief report: The temporal relationships between sleep, cortisol, and lung functioning in youth with asthma

Abstract

Objectives: This study tested the directionality of the association between sleep and health outcomes in youth with asthma. Method: Thirty-eight youth with asthma (aged 9-19) completed a daily diary study on sleep, asthma symptoms, peak expiratory flow (PEF) measures, and salivary cortisol samples. Results: Greater quantity of sleep predicted lower PEF% [β(32)=-.33, p=.02], and lower daily cortisol output [β(33)=-.31, p=.07] the following day. Additionally, poorer self-reported sleep quality predicted more severe symptoms the next day [β(33)=.27, p=.05]. In contrast, PEF%, cortisol, and asthma symptoms did not significantly predict self-reported sleep quantity or quality the next night. Conclusions: Results suggest that sleep may affect subsequent health outcomes, rather than asthma impacting subsequent sleep, indicating the potential benefits of targeting sleep behaviors in youth with asthma. © The Author 2007.