Hormonal Mechanisms of Sleep Restriction - Axis Study

Sleep restriction increases evening cortisol and decreases testosterone. These are the main catabolic and anabolic hormones in men, respectively. This catabolic-anabolic imbalance likely leads to metabolic and reproductive ill-health. The hypothalamic-pituitary-end organ (adrenal or testis) mechanisms that must underpin these changes are unknown. This study will administer drugs to clamp the function of each of these nodes to determine the regulatory changes that have occurred with sleep restriction. Even though the study is randomized order in design, the main comparison is before and after sleep restriction under each of these clamp conditions. Participants are admitted to the chronobiology laboratory where they are given 1 night of 10 hours sleep opportunity, followed by 4 nights of 4 hours sleep opportunity. Up to 80 participants (assuming twenty different participant for each of the 4 clamp conditions) can be enrolled. However, participants will be allowed an opportunity to be randomized to all 4 conditions so that as few as 20 participants may be required. Urn randomization will be used to ensure that 20 different participants are involved in each of the 4 conditions.