Clinical Trial Details
— Status: Recruiting
Administrative data
NCT number |
NCT04921215 |
Other study ID # |
R01HL146772 |
Secondary ID |
|
Status |
Recruiting |
Phase |
N/A
|
First received |
|
Last updated |
|
Start date |
June 14, 2021 |
Est. completion date |
September 2025 |
Study information
Verified date |
January 2024 |
Source |
Rush University Medical Center |
Contact |
n/a |
Is FDA regulated |
No |
Health authority |
|
Study type |
Interventional
|
Clinical Trial Summary
Circadian clocks shift later (delay) with the progression of puberty; this shift contributes
to late sleep onsets in older adolescents. Early school start times, however, force teenagers
to awaken earlier than their spontaneous wake time and the opportunity for sleep shortens.
Chronic circadian misalignment and sleep restriction are at their peak during late
adolescence, and are associated with various negative outcomes. Morning bright light exposure
from light boxes can shift rhythms earlier (phase advance) to facilitate earlier sleep onset,
and reduce circadian misalignment and the associated risks. Studies of adults, however,
indicate that restricted sleep and exposure to evening light due to late bedtimes make
morning bright light less effective in producing advances. Pilot data collected from
adolescents mimic this finding, but also suggest that staying awake late in normal household
lighting and the subsequent sleep restriction before and during a 3-day morning bright light
regimen, can shift the system in the wrong direction (phase delay). The overarching goal of
this study is to examine the dose of sleep restriction and evening household light that
prevents the desired phase advance to morning bright light in adolescents aged 14-17 years.
Study 1 aims to construct a sleep restriction with normal household evening light
dose-response curve to determine the point at which morning bright light begins to lose its
effectiveness. The investigators hypothesize that the circadian system will advance with
sufficient sleep, but with increasing sleep restriction/evening light, circadian rhythms will
not shift or will delay despite the phase advancing morning bright light. Study 2 will test
whether reducing evening light exposure by wearing sunglasses before bedtime during sleep
restriction can facilitate phase advances. The main outcome measures to build the
dose-response curve will be phase shifts of the central circadian clock marked by the dim
light melatonin onset (DLMO) and total sleep time measured from actigraphy in the laboratory.
Secondary outcomes include cognitive performance, sleepiness, and mood.
Description:
Circadian clocks shift later (delay) with the progression of puberty; this shift contributes
to late sleep onsets in older adolescents. Early school start times, however, force teenagers
to awaken earlier than their spontaneous wake time and the opportunity for sleep shortens.
Indeed, a majority of adolescents in the U.S. are chronically sleep deprived, getting 1-2
hours less sleep than recommended. Also, many adolescents wake for school at the "wrong"
circadian time. Chronic circadian misalignment and sleep restriction are at their peak during
late adolescence, and are associated with morning daytime sleepiness, poor academic
performance, conduct problems, depressed mood, suicidal ideation, substance use, and obesity.
Morning bright light exposure from light boxes can shift rhythms earlier (phase advance) to
facilitate earlier sleep onset, and reduce circadian misalignment and the associated risks.
The investigators constructed the first phase response curve (PRC) to light for adolescents
and determined that the optimal time for bright light exposure to produce phase advances was
about 1 hour before habitual wake and light should be avoided around the time of habitual
bedtime because it causes rhythms to shift later (delay). Studies of adults, however,
indicate that restricted sleep and exposure to evening light due to late bedtimes - two
classic features of older adolescent sleep - make morning bright light less effective in
producing advances. Pilot data collected from adolescents mimic this finding, but also
suggest that staying awake late in normal household lighting and the subsequent sleep
restriction before and during a 3-day morning bright light regimen, can shift the system in
the wrong direction (phase delay). The overarching goal of this study is to examine the dose
of sleep restriction and evening household light that prevents the desired phase advance to
morning bright light in adolescents aged 14-17 years. Study 1 aims to construct a sleep
restriction with normal household evening light dose-response curve to determine the point at
which morning bright light begins to lose its effectiveness. Following a baseline week with
10-hour sleep opportunities, participants will keep the same wake time but be randomly
assigned to one of 4 bedtimes which will be the same or later than baseline to produce 4
levels of sleep restriction with evening light (0, 1.5, 3, or 4.5 hours). After 2 nights, the
sleep schedule will gradually shift earlier over 3 nights, and participants will receive
bright light each morning. The investigators hypothesize that the circadian system will
advance with sufficient sleep, but with increasing sleep restriction/evening light, circadian
rhythms will not shift or will delay despite the phase advancing morning bright light. Study
2 will test whether reducing evening light exposure by wearing sunglasses before bedtime
during sleep restriction can facilitate phase advances. Study 2 will test the same 4 "doses"
of sleep restriction. The main outcome measures to build the dose-response curve will be
phase shifts of the central circadian clock marked by the dim light melatonin onset (DLMO)
and total sleep time measured from actigraphy in the laboratory. Secondary outcomes include
cognitive performance, sleepiness, and mood.