Facilitating Adjustment to Simulated Jet Lag
- Conditions
- Circadian Rhythm Sleep Disorder, Jet Lag Type
- Interventions
- Behavioral: Bright LightBehavioral: Bright Light + Exercise + MelatoninBehavioral: Control
- Registration Number
- NCT05382923
- Lead Sponsor
- University of Arizona
- Brief Summary
The aims of this study are to compare 3 different treatments for circadian adjustment to a laboratory protocol which will mimic westward air travel across 8 time zones. One treatment will involve simply following the new schedule for 3 days. Another treatment will also involve exposure to bright light for 1 hour per day. A third treatment will involve exposure to bright light + exercise for 1 hour per day + consuming a melatonin tablet. Adjustment to the shifted schedule will be assessed by comparing measures of sleep, mood, mental performance, physical performance, and timing of melatonin across the 3 treatment conditions.
- Detailed Description
Design Overview. Following a 1 week home baseline, N=36 young adults will spend 6 days in the laboratory (Figure 3 and Table 1). Following am 8 h baseline polysomnographic recording (PSG) on Night 1, participants will undergo a 26 h baseline circadian assessment via an ultrashort sleep-wake protocol involving 2 h wake intervals and 1 h sleep intervals, repeated throughout the protocol. Following baseline circadian assessment, participants will be placed on a 16 h wake-8 h sleep schedule in which the wake-sleep and light-dark schedule is delayed 8 h for 3 days (analogous to traveling 8 time zones west). Participants will be randomized to one of 3 treatments (n=12 per treatment) administered each of the 3 days of the shifted schedule: (1) placebo control, (2) bright light, and (3) bright light + exercise + melatonin. PSG recording will occur on the last night of the shifted schedule, followed by an end-of-study 26 h ultrashort sleep wake schedule. On baseline Day 1 and Days 2-3 of the shifted schedule, sleepiness, mood, and mental performance will be assessed every 3 h during wake. During all four 8 h sleep periods, sleep will also be recorded with the Z-machine, which assesses sleep stages from 3 EEG electrodes. During the ultrashort sleep-wake schedules, mental performance, physiological performance, urinary aMT6s, mood, and sleepiness will be measured around-the-clock.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- All
- Target Recruitment
- 36
- age 18-45 years
- At least moderate level of habitual physical activity (twice per week, 20 min of aerobic exercise at 60% of maximal effort or higher
(1)Having more than one risk factor for coronary artery disease: (2) having any symptom or sign of cardiopulmonary disease; (3) recent shift-work experience (previous 2 months) or travel across multiple time zones (previous 4 weeks); (4) having an abnormal sleep-wake schedule (i.e., reported bedtime before 9:00 pm or after 2:00 am; wake time before 5:00 am or after 10:00 am); (5) being an extreme night owl or morning lark, as assessed by the Horne-Ostberg Mornngness-Eveningness Scale;70 (6) having a high risk sleep apnea or another sleep disorder; (7) depressed mood [Center for Epidemiologic Studies-Depression Scale (CES-D) > 16];71 (7) use of medications likely to distort melatonin excretion or cardiovascular responses to exercise; (8) use of sleeping pills more than 1 night per week; (9) having high sensitivity to light; (10) abuse of alcohol or drugs (amount per week; related problems such as missing work); (11) any physical or mental health condition that would contraindicate participation in exercise or other rigors of the experiment.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Bright Light Alone Bright Light Bright light administered with Re-Timer glasses for 1 hour on 3 consecutive days. Following the 8 hour delay of the light/dark and sleep/wake cycle in the laboratory, the light will be administered, on average at 5:30-6:30 pm, 7:00-8:00 pm, and 9:30-10:30 pm, respectively on these three days. Bright Light + Exercise + Melatonin Bright Light + Exercise + Melatonin Bright light will be administered with Re-Timer glasses for 1 hour on 3 consecutive days. Following the 8 hour delay of the light/dark and sleep/wake cycle in the laboratory, the light will be administered, on average at 5:30-6:30 pm, 7:00-8:00 pm, and 9:30-10:30 pm, respectively on these three days. Exercise (1 hour at 65-75% heart rate reserve) will be administered on 3 consecutive, at 1:30-2:30 pm, 4:00-5:00 pm, and 6:30-7:30 pm on these days. Melatonin (0.5 mg) will be administered at 6 am, 8:30 am, and 11:00, on the 3 days. Placebo Control Control Dim red light will be administered with Re-Timer glasses for 1 hour on 3 consecutive days. Following the 8 hour delay of the light/dark and sleep/wake cycle in the laboratory, the light will be administered, on average at 5:30-6:30 pm, 7:00-8:00 pm, and 9:30-10:30 pm, respectively on these three days. Placebo tablets (0.5 mg) will be administered at 6 am, 8:30 am, and 11:00, on the 3 days.
- Primary Outcome Measures
Name Time Method Change (shift) in the acrophase of the rhythm of the median reaction time 6.5 days Change (shift) in the cosine fitted peak for the assessments (psychomotor vigilance, every 3 h) taken during days 2-3 compared with the assessments taken during days 6-7
Change in sleep duration 5 days Change in total sleep time assessed during night one in the lab and night 5 in the lab duration
Change (shift) in the acrophase of urinary 6-sulphatoxymelatonin (aMT6s) excretion 6.5 days Change (shift) in the cosine fitted peak for the assessments (every 90 min) during lab days 2-3 compared with the assessments taken during days 6-7
- Secondary Outcome Measures
Name Time Method Change (shift) in the acrophase of the Total Mood Disturbance composite scale of on the Profile of Mood States questionnaire 5 days Change (shift) in the cosine-fitted peak of the rhythm of total mood disturbance assessed during days 2-3 compared with total mood disturbance assessed during days 6-7
Change (shift) in the acrophase of the Stanford Sleepiness Scale 5 days Change (shift) in the cosine-fitted peak of the rhythm of the Stanford Sleepiness Scale assessed during days 2-3 compared with the Stanford Sleepiness Scale mood disturbance assessed during days 6-7
Change (shift) in the acrophase of the Wingate Anaerobic Performance Test 5 days Change (shift) in the cosine-fitted peak of the rhythm of the Wingate Anaerobic Performance Test assessed on days 2-3 and day 6-7.
Change in sleep recorded with z-machine 5 days Z machine recorded sleep with electrodes on the mastoid bones. Change in sleep assessed in eight 1-h sleep intervals on days 2-3 and days 6-7
Trial Locations
- Locations (1)
Center Sleep and Circadian Sciences
🇺🇸Tucson, Arizona, United States