Hormonal Mechanisms of Sleep Restriction - Axis Study in Older Men and Postmenopausal Women

Sleep restriction and its consequences are major public health problems, especially in older adults. Among the more severe physiological sequelae of sleep restriction is the development of insulin resistance. The mechanisms by which sleep restriction leads to increased insulin resistance are unknown, especially in vulnerable older adults; such research informs development of targeted interventions against the sleep loss/insulin resistance link. 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 40 participants can be enrolled. However, participants will be allowed an opportunity to be randomized to all 4 conditions so that as few as 10 participants may be required. We anticipate 5 men and 5 women will be enrolled assuming each undergoes all 4 clamp conditions.