Sleep Length and Circadian Regulation in Humans

Sleep Disorders Clinical Trial

— HAM  

Official title:

Sleep Length and Circadian Regulation in Humans

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT00843843
• Other study ID #: HL083971
• Secondary ID: HL083971
• Status: Completed
• Phase: N/A
• First received: February 12, 2009
• Last updated: February 9, 2016
• Start date: March 2008
• Est. completion date: February 2014

Study information

• Verified date: February 2016
• Source: Rush University Medical Center
• Contact: n/a
• Is FDA regulated: No
• Health authority: United States: Institutional Review Board
• Study type: Interventional

Clinical Trial 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.

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.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 16
• Est. completion date: February 2014
• Est. primary completion date: February 2014
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: Both
• Age group: 18 Years to 45 Years

Eligibility

Inclusion Criteria:

• healthy adult volunteers

Exclusion Criteria:

• color blindness with the Ishihara test

• obese people (BMI > 30)

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Crossover Assignment, Masking: Single Blind (Subject), Primary Purpose: Basic Science

Related Conditions & MeSH terms

• Parasomnias
• Sleep Disorders

Intervention

Device:
• Bright light box
Bright light of about 5000 lux, administered while sitting at a desk.

Locations

Country	Name	City	State
United States	Biological Rhythms Research Laboratory, RUMC	Chicago	Illinois

Sponsors (2)

Lead Sponsor	Collaborator
Rush University Medical Center	National Heart, Lung, and Blood Institute (NHLBI)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Dim Light Melatonin Onset (Hours)	Gold standard marker of circadian timing	12 days from baseline to final dim light melatonin onset	No
Secondary	Psychomotor Vigilance	Fastest 10% reaction time (msec)	after short or long nights	No