Repeated Challenge of Insufficient Sleep: Endothelial Effects

Study Overview
=================
Brief Summary
-----------------
The 24-hour-a-day, 7-day a week, work-world arrived within our lifetimes, and is here to stay. Americans are working more and more, frequently at multiple jobs. The pattern of short sleep during the week followed by attempts to recover on the weekend is in common practice, but we know little of the associated health risks. What is the cost in terms of increasing known risk markers for cardiovascular disease, of repeated nights of insufficient sleep, and is this cost compounded with repetition, without adequate recovery? Evidence is accumulating to suggest that short sleep duration is linked to the development of metabolic and inflammation-associated diseases, such as cardiovascular disease. Mechanisms involved in the development of cardiovascular disease include impaired vascular function and inflammation. The current proposal is designed to investigate the effects of repeated periods of short nocturnal sleep duration in 4 cycles (each cycle consisting of 3 nights of 4 hours of sleep opportunity per night), and each cycle of short sleep followed by a single night of recovery sleep. Vascular reactivity will be assessed using brachial artery flow mediated dilation, and microcirculatory vasodilation will be assessed using perfusion imaging techniques. The dependence of IL-6 and sVCAM-1 as measured in peripheral circulation, on vascular function, will also be investigated.

Detailed Description
-----------------
Due to work, family, social and community obligations, millions of Americans cut back on sleep for several nights in a row before having an opportunity to catch up. When the opportunity does arise, it may only be for a single night, before the cycle of insufficient sleep repeats. This study investigated what happens to human biology when insufficient sleep becomes chronic and opportunities for recovery sleep are intermittent. It also investigated recovery sleep itself, and the biological processes involved in reversing the effects of an accumulated sleep deficit due to insufficient sleep duration.

Official Title
-----------------
Repeated Challenge of Insufficient Sleep: Effects on Endothelial Function

Conditions
-----------------
Repeated Short Sleep Schedule

Intervention / Treatment
-----------------
* Behavioral: repeated cycles of short sleep


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Healthy volunteers Regular sleep-wake schedule Exclusion Criteria: Diseases or medical conditions, including sleep disorders Current smoking Pregnant or nursing Recent time zone travel or shift work Regular medication use High blood pressure

Ages Eligible for Study
-----------------
Minimum Age: 25 Years
Maximum Age: 55 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: normal sleep<br>Subjects have 8 hours of sleep opportunity per night | Behavioral: repeated cycles of short sleep<br>* - 3 nights of 4 hours of sleep followed by a single recovery night of 8 hours; repeated for 4 cycles<br>|
| Experimental: cycles of sleep restriction<br>subjects are exposed to bouts of reduced sleep duration. The sleep loss is the intervention (experimental challenge). | Behavioral: repeated cycles of short sleep<br>* - 3 nights of 4 hours of sleep followed by a single recovery night of 8 hours; repeated for 4 cycles<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vascular reactivity |  | 22 days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Inflammation |  | 22 days |