Experimentally increasing sedentary behavior results in decreased sleep quality among young adults

Objective: Sleep has been shown to influence cardiometabolic function, and physical activity and sedentary behavior have both been shown to epidemiologically influence sleep. However, no study has experimentally evaluated the effects of sedentary behavior on sleep quality, which was this study's purpose. Methods: This study employed a 2-group parallel randomized controlled intervention protocol; young adult (18-35 years old) participants confirmed to be active were randomly assigned into a sedentary behavior intervention group (n = 26) or a control group (n = 13). The intervention group was asked to minimize steps to <= 5000 steps/day for one week whereas the control group was asked to continue normal physical activity levels for one week. Both groups completed the Pittsburgh Quality Sleep Index (PSQI) pre- and post-intervention. The intervention group resumed normal physical activity levels for one week post-intervention. Results: A significant group x time interaction effect was observed (F = 4.49, P = 0.04), with contrast tests indicating significant PSQI change score in the intervention group. Specifically, PSQI scores significantly decreased by 3.16 points (representing improved sleep quality) from Visit 2 to Visit 3 (P < 0.001) in the intervention group. Conclusion: Active young adults who removed structured exercise and significantly decreased their step counts (e.g., increased their amount of time spent being sedentary) for one week experienced significant decreases in sleep quality. The present findings underscore the importance of maintaining regular physical activity for optimal sleep quality. (C) 2017 Elsevier Ltd. All rights reserved.