Effect of sleep variability on peripheral vascular function during acute cycling exercise

Sleep variability is defined as the variance of night-to-night total sleep time. Recent investigations have suggested an association between high sleep variability and impaired vascular function at rest and following exercise. The aim of this study was to determine the effect of sleep variability on peripheral vascular function during acute exercise. Upon an initial screening visit, 32 healthy young adults (20 M, 12 F; age: 22.5 ± 5 y) completed a maximal cycling exercise test and were instructed to maintain normal sleep behavior for the following 7 days. During the 7-day period, sleep data was collected via wrist-worn actigraphy, and the five weekdays were used for analysis. On the morning after the 7-day period, participants reported to the laboratory to examine vascular function at rest and during moderate and vigorous intensity cycling exercise. Participants were categorized as having either lower (<55 minutes) or higher (≥55 minutes) sleep variability. Comparisons between groups were made using independent sample two-tailed t-tests and Pearson correlations to identify relationships. No differences were observed in skeletal muscle microvascular vasodilation at rest (p = 0.784) or seated resting systolic blood pressure (p = 0.398). While the change in systolic blood pressure was correlated with sleep variability (r = 0.448, p = 0.012), the change in systolic blood pressure during exercise (p = 0.227) along with skeletal muscle oxygenation changes during moderate (p = 0.628) and vigorous intensity exercise (p = 0.073) were not significantly different between sleep variability groups. In summary, our results signify that sleep variability does not have a significant influence on peripheral microvascular function or blood pressure at rest or during exercise in healthy college-aged adults.