Clinical trial NCT01119365: Bright Light as a Countermeasure for Circadian Desynchrony
Official title: Bright Light as a Countermeasure for Circadian Desynchrony
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Healthy
Keywords: Healthy controls
Lead sponsor: VA Palo Alto Health Care System
Sponsor class: FED
Collaborators: name: Stanford University
name: Palo Alto Veterans Institute for Research
First posted: 2010-05-07
Enrollment: 300
Sex: ALL
Minimum age (years): 18
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: Light is the primary means by which the internal circadian clock remains aligned ("entrained") with the external world. Misalignment of this internal clock can occur during situations such as shift work and jet travel across multiple time zones (jet lag). The purpose of this study is to examine how sequences of brief flashes of light can affect entrainment of the clock.


Eligibility criteria: Inclusion Criteria:

* Good health
* Normal hearing

Exclusion Criteria:

* Sleep disorder
* Extreme chronotype
* Regular smoker
* Depression
* Alcohol abuse
* Illegal drug use

Primary outcomes:
measure: Circadian phase
timeFrame: 2 days
Secondary outcomes:
measure: Alertness
timeFrame: 1 hour
Other outcomes:
Locations:
city: Palo Alto
country: United States
facility: VA Palo Alto Health Care System
state: California
Study officials:
affiliation: Stanford University/VAPAHCS
name: Jamie M Zeitzer, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Zeitzer JM, Dijk DJ, Kronauer R, Brown E, Czeisler C. Sensitivity of the human circadian pacemaker to nocturnal light: melatonin phase resetting and suppression. J Physiol. 2000 Aug 1;526 Pt 3(Pt 3):695-702. doi: 10.1111/j.1469-7793.2000.00695.x.
citation: Cajochen C, Zeitzer JM, Czeisler CA, Dijk DJ. Dose-response relationship for light intensity and ocular and electroencephalographic correlates of human alertness. Behav Brain Res. 2000 Oct;115(1):75-83. doi: 10.1016/s0166-4328(00)00236-9.
citation: Zeitzer JM, Khalsa SB, Boivin DB, Duffy JF, Shanahan TL, Kronauer RE, Czeisler CA. Temporal dynamics of late-night photic stimulation of the human circadian timing system. Am J Physiol Regul Integr Comp Physiol. 2005 Sep;289(3):R839-44. doi: 10.1152/ajpregu.00232.2005. Epub 2005 May 12.
citation: Zeitzer JM, Ruby NF, Fisicaro RA, Heller HC. Response of the human circadian system to millisecond flashes of light. PLoS One. 2011;6(7):e22078. doi: 10.1371/journal.pone.0022078. Epub 2011 Jul 8.
citation: Zeitzer JM, Fisicaro RA, Ruby NF, Heller HC. Millisecond flashes of light phase delay the human circadian clock during sleep. J Biol Rhythms. 2014 Oct;29(5):370-6. doi: 10.1177/0748730414546532. Epub 2014 Sep 16.
citation: Najjar RP, Zeitzer JM. Temporal integration of light flashes by the human circadian system. J Clin Invest. 2016 Mar 1;126(3):938-47. doi: 10.1172/JCI82306. Epub 2016 Feb 8.
citation: Joyce DS, Spitschan M, Zeitzer JM. Duration invariance and intensity dependence of the human circadian system phase shifting response to brief light flashes. Proc Biol Sci. 2022 Mar 9;289(1970):20211943. doi: 10.1098/rspb.2021.1943. Epub 2022 Mar 9.