Goal of this study is to test the hypothesis that repeated exposure to cycles of insufficient sleep increases susceptibility to a variety of disease states by progressively compromising the integrity of stress response systems.

Inclusion Criteria:

• Body mass index (BMI) between 18.5 and 30 kg/m2
• For female participants: regular menstrual cycles
• Daily sleep duration in the normal range
• Blood chemistry in the normal range

Exclusion Criteria:

• Active infection/disease
• History of psychiatric, neurological, pain-related, immune, or cardiovascular disease; significant allergy
• Pregnant/nursing
• Respiratory disturbance index of >5 events/hour on polysomnographic sleep study, leg movements with arousal >10/hour; sleep efficiency <80%
• Regular medication use other than oral contraceptives
• Donation of blood or platelets 3 month prior to or in-between study arms