Menstrual-phase-dependent Differences in Response to Sleep Loss

This study is designed to assess how healthy premenopausal women respond to different patterns of sleep loss at different times in the menstrual cycle.

Inclusion Criteria: * Female * 18-35 years old * Regular menstrual cycle between 26-35 days in duration * Not using any form of hormonal contraception for at least the prior 3 months * Regular sleep patterns (7-9 hours/night) * Not taking any medications or supplements * Weight \>110 lb * BMI between 18.5 and 29.5 kg/m2 Exclusion Criteria: * Primary sleep disorder * History of shift work * Transmeridian travel in the previous 3 months * Presence of acute or chronic disease, including but not limited to: diabetes, metabolic disorders, psychiatric illness, reproductive disorders * Current pregnancy, \< 6 months postpartum, and/or breastfeeding * Blood donation in the past 8 weeks * Extreme morning or evening chronotype