Sleep Length and Circadian Regulation in Humans

NCT ID: NCT00843843

Last Updated: 2016-03-08

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 16 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2008-03-31
• Study Completion Date: 2014-02-28

Brief Summary

This research will examine why sleep restriction reduces the body clock's response to bright light. The results will enable the optimization of the bright light treatment of people who suffer from circadian rhythm sleep disorders, which include shift work sleep disorder, jet lag, delayed sleep phase syndrome and winter depression, thereby improving public health and safety, well-being, mood, mental function, and quality of life.

Detailed Description

Millions of Americans suffer from circadian rhythm sleep disorders, which include shift work sleep disorder, jet lag, delayed sleep phase syndrome and possibly winter depression. These conditions are typically characterized by persistent insomnia and/or excessive daytime sleepiness, impaired performance, and gastrointestinal distress. These negative symptoms result from a misalignment between the timing of the external social world and the timing of the internal circadian (body) clock. Circadian rhythm sleep disorders are effectively treated with bright light, which phase shifts the circadian clock, thereby realigning it with the timing of the external social world.

It is widely recognized that social influences have led to an increasing prevalence of sleep restriction in modern society. We recently demonstrated for the first time that short sleep episodes, when compared to long sleep episodes, markedly reduce phase advances to bright light. Thus when people cut their sleep short, they inadvertently reduce their circadian responsiveness to bright light. The mechanism(s) behind these reduced phase shifts to light are unknown. However, there are at least two aspects of short sleep episodes that could be responsible for this effect. First, short sleep episodes are associated with partial sleep deprivation. Second, as humans sleep with their eyes closed and are usually exposed to light when awake, short sleep episodes are also associated with short dark lengths. Our overall goal is to determine the biobehavioral mechanisms by which short sleep episodes impair phase shifts to bright light. Specific Aim 1 is to determine the effect of partial sleep deprivation on phase advances to light, while controlling for dark length. Specific Aim 2 is to determine the effect of short dark lengths on phase advances to light while minimizing sleep deprivation. We will estimate the timing of the human circadian clock by measuring salivary melatonin, a neuroendocrine hormone released from the pineal gland, and collecting measures of sleep via actigraphy, and sleepiness, mood, gastrointestinal distress and cognitive performance via computerized assessment.

Characterization of the separate effects of sleep deprivation and dark length on circadian phase shifts to light in humans is critical to understanding how humans respond to light during their daily life activities. Furthermore, the findings of this research will produce important and practical recommendations for avoiding decrements to phase shifts to light, thereby optimizing the bright light treatment of circadian rhythm sleep disorders, and thus improving public health and safety, well-being, mood, cognitive function, and quality of life.

Conditions

Sleep Disorders

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: BASIC_SCIENCE
• Blinding Strategy: SINGLE

Study Groups

9 hour sleep, then 3 hour nap and 6 hour sleep

Group Type: ACTIVE_COMPARATOR

Bright light box

Intervention Type: DEVICE

Bright light of about 5000 lux, administered while sitting at a desk.

3 hour nap and 6 hour sleep, then 9 hour sleep

Group Type: ACTIVE_COMPARATOR

Bright light box

Intervention Type: DEVICE

Bright light of about 5000 lux, administered while sitting at a desk.

Interventions

Bright light box

Bright light of about 5000 lux, administered while sitting at a desk.

Intervention Type: DEVICE

Eligibility Criteria

Inclusion Criteria

• healthy adult volunteers

Exclusion Criteria

• color blindness with the Ishihara test
• obese people (BMI > 30)

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 45 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: Yes

Sponsors

National Heart, Lung, and Blood Institute (NHLBI)

NIH

Sponsor Role: collaborator

Rush University Medical Center

OTHER

Sponsor Role: lead

Responsible Party

Helen Burgess

Associate Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Helen Burgess, PhD

Role: PRINCIPAL_INVESTIGATOR

Rush University Medical Center

Locations

Biological Rhythms Research Laboratory, RUMC

Chicago, Illinois, United States

Countries

United States

Other Identifiers

HL083971

Identifier Type: -

Identifier Source: secondary_id

HL083971

Identifier Type: -

Identifier Source: org_study_id