Sleep Timing on Energy Intake and Energy Expenditure

Studies in healthy young adults have shown that abnormal and undesirable physiological changes are a result of chronic sleep curtailment, with implications on inflammatory status, blood glucose regulation, circulating free fatty acids, and insulin sensitivity. Epidemiological studies suggest an increase in energy intake with shortened, sleep and this has been associated with weight gain. Interestingly most studies examining sleep restriction do not consider whether the restricted sleep is due to sleep delay or an advanced wake time. This study will investigate the change in physical activity or food intake during a period of sleep restriction. To date only one study has addressed this question but they only examined one study night and followed their subjects for only 24 hr. The objective of the proposed project is to examine the effects of shortened sleep on potential changes in physical activity and energy intake. The investigators hypothesize that after several nights of short sleep that different strategies are employed to remain awake and these strategies will also vary whether bed time was delayed or wake time was advanced. Aim 1: To examine the effects of sleep timing on energy intake and expenditure during periods of sleep restriction