Late chronotype
Conditions
Interventions
Group 1: 45-minutes low-intensity morning exercise in dim-light (<10 lux) approximately 10-15 minutes after awakening. Low-intensity exercise (walking on a treadmill) is individually defined at 30% to
Sponsors
University of Basel, Department of Sport, Exercise, and Health
Eligibility
Sex/Gender
Male
Age
15 Years to 18 Years
Inclusion criteria
Inclusion criteria: Male Aged 15-18 years absence of sleep and other psychological disorders sedentary: < 60 min physical activity per week Late chronotype
Exclusion criteria
Exclusion criteria: Physical conditions that need medical advice before being physically active (e.g., resting heart rate > 90 BPM), intake of psychopharmaceuticals, as some antidepressants impact the biotransformation of melatonin. Female adolescents will not be considered for recruitment, as modification in circadian rhythms across the menstrual cycle require an assessment during the luteal phase. Being bound to the school holiday period, this would impose significant organizational challenges. A further exclusion criteria is a physically active individual (>60min moderate-to-vigorous physical activity per week) and having a early or regular chronotype
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Dim light melatonin onset (DLMO) is measured via salivary DLMO samples taken half-hourly in dim light (<10 lux) using salivettes (Sarstedt, Newton, NC, USA) starting 4 hrs before and finishing 2 hrs after adolescent`s bedtime (Crowley et al., 2016). Participants are seated for at least 5 min before and during each saliva sample, to minimize the masking effects of physical movement on endogenous melatonin production. Food and water are consumed only after saliva collection to reduce contamination or dilution of the sample. Participants are instructed to place the swab in their mouth and accumulate saliva for 2 min. After collection, samples will be stored frozen at -20°C. This procedure will be replicated during follow-up assessments. For analysis, samples will be thawed and centrifuged for 10 min at 2500 rpm, the swabs removed from the casing, and the supernatant retained. A sensitive (4.3 pM) direct radioimmunoassay (RIA) using reagents from Buhlmann Laboratories AG (Allschwil, Switzerland) (Voultsios et al., 1997) will be used to measure melatonin in the saliva. | — |
Secondary
| Measure | Time frame |
|---|---|
| 1. Evening sleepiness will be assessed subjectively via the Karolinskia Sleepiness Scale (KSS; Åkerstedt & Gillberg, 1990) in the 3 hrs before bedtime. 2. Objective evening vigilance will be measured immediately after each KSS rating. The computerized Go/NoGo task (E-Prime v1.2, Psychology Software Tools, Inc., Pittsburgh, PA, USA, 2006) measures sustained attention in relation to inhibitory functions and consists of two visual stimuli presented in random order. 3. Mood/daytime functioning will be assessed via the Depression, Anxiety, and Stress Scale (DASS-21) to detect secondary outcomes of morning exercise and/or circadian phase shift on mood. | — |
Countries
Australia
Contacts
Public ContactChristin Lang
University of Basel, Department of Sport, Exercise, and Health
Outcome results
None listed