Effect of Sleep Extension on Body Weight and Learning in Children (More2Sleep) (More2Sleep)

A Randomized Controlled Trial of Sleep Extension to Regulate Body Weight and Improve Learning in School-aged Children

More2Sleep is a randomized, controlled, parallel trial with two groups (sleep extension vs control) including 142 school-aged children (6-12 years) who have a BMI above average, defined as age- and sex-specific BMI Z-score above zero using WHO reference standards, and habitually sleep for ≤ 9 h/night. Data will be collected before and after a 3-month sleep extension intervention, and after a 6-month follow-up (at months 0, 3, and 9). The collection of data is mainly related to the main study. However, some optional examinations will be conducted on a first come, first serve basis, consisting of substudy-I (metabolic mechanisms, n=60) and substudy-II (learning mechanisms, n=142).

The primary objective is to assess the effects of sleep extension by ~45 min/night, achieved by going to bed 60-90 min earlier, on adiposity and learning ability in school-aged children who have a BMI for age and sex above average, and sleep less than recommended for their age.

Study Overview

• Status: Recruiting
• Conditions: Child Behavior; Child Development; Child Obesity; Sleep Duration
• Intervention / Treatment: Behavioral: Sleep extension

• Study Type: Interventional
• Enrollment (Estimated): 142
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Faidon Magkos, PhD; Phone Number: +45 35 33 36 71; Email: fma@nexs.ku.dk
• Study Contact Backup: Name: Eva Leedo-Townend, MSc; Phone Number: +45 35 33 35 68; Email: elt@nexs.ku.dk

Study Locations

• Denmark
  • Copenhagen, Denmark, 2200
    • Recruiting
    • University of Copenhagen
    • Principal Investigator: Faidon Magkos, PhD
    • Contact: Faidon Magkos, PhD; Phone Number: +45 35 33 36 71; Email: fma@nexs.ku.dk
    • Sub-Investigator: Jesper Lundbye-Jensen, PhD
    • Sub-Investigator: Poul Jennum, MD
    • Contact: Jesper Lundbye-Jensen, PhD; Phone Number: +45 35 32 73 30; Email: jlundbye@nexs.ku.dk
  • Copenhagen, Denmark, 1958
    • Recruiting
    • University of Copenhagen
    • Principal Investigator: Faidon Magkos, PhD
    • Contact: Faidon Magkos, PhD; Phone Number: +45 35 33 36 71; Email: fma@nexs.ku.dk
    • Sub-Investigator: Jesper Lundbye-Jensen, PhD
    • Sub-Investigator: Poul Jennum, MD
    • Contact: Eva Leedo-Townend, MSc; Phone Number: +45 35 33 35 68; Email: elt@nexs.ku.dk
  • Hvidovre, Denmark, 2650
    • Recruiting
    • Faidon Magkos
    • Principal Investigator: Faidon Magkos, PhD
    • Contact: Faidon Magkos, PhD; Phone Number: +45 35 33 36 71; Email: fma@nexs.ku.dk
    • Sub-Investigator: Jesper Lundbye-Jensen, PhD
    • Sub-Investigator: Poul Jennum, MD
    • Sub-Investigator: Kathrine Madsen, PhD
    • Sub-Investigator: Hartwig Siebner, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age: 6-12 years old (inclusive range).
• Weight status: having a BMI above average, defined as an age- and sex-specific BMI Z-score above zero using reference standards from the WHO.
• Sleep duration: sleeping ≤9 h/night on the basis of sleep diaries filled in by the children's parents, based on recommendations by the American Academy of Sleep Medicine and the Sleep Health Foundation.

Exclusion Criteria:

• Any genetic, neurological, endocrinological or psychiatric condition that affects growth, metabolism, eating behaviors, cognitive function, or body weight (for example: dwarfism, epilepsy, attention deficit hyperactivity disorder, head trauma, β-thalassemia, hypothyroid-ism, hyperthyroidism, type I diabetes).
• Any sleep-related disorder (for example: obstructive sleep apnea, parasomnias, narcolepsy, restless leg syndrome).
• Regular use of prescribed or over-the-counter medications that influence study outcomes.
• Irregular school schedule.
• If a child's parents live separately, the child is allowed to sleep at both households. How-ever, if one of the parents does not wish to carry out the sleep intervention and follow given instructions, then the child should only sleep at their household Friday, Saturday and/or Sunday night.
• In the circumstance where the child does not speak or understand Danish, the child's parents do not have to speak or understand Danish, as long as both parties can speak and understand English.
• Participation in other research studies.
• Metal implants and claustrophobia (only for substudy-II).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Sleep extension; The sleep extension group (n=71) will receive a behavioral intervention focusing on parents putting their children to bed earlier by 60-90 minutes. Parents will be instructed only to alter their children's daily sleeping routine, and not to directly alter their diet and physical activity habits. Children and their parents will receive a behavioral intervention consisting of 6 sessions, including both in-person and virtual sessions, which will be scheduled based on the family's availability and to accommodate practicalities.	Behavioral: Sleep extension; The sleep extension group will receive a behavioral intervention focusing on parents putting their children to bed earlier by 60-90 minutes. Previous studies have found this change in daily sleeping routine to be feasible and to result in 40-45 min more actual sleep. Children and their parents will receive a behavioral intervention consisting of 6 sessions, including both in-person and virtual sessions, which will be scheduled based on the family's availability and to accommodate practicalities, e.g., potential sickness or cancellations. The first two sessions will occur at the beginning of the study. These initial sessions will focus on effective behavioral strategies to enhance sleep time, including goal setting (e.g., bedtimes and wake-up times), problem-solving and preplanning, stimulus control (i.e., sleep hygiene recommendations), and positive reinforcement. Subsequent sessions will be planned with the families to occur regularly during the 12-week intervention.
No Intervention: Control; The control group (n=71) will follow their habitual sleeping schedule. Parents will be instructed not to alter their children's daily sleeping routine, or their diet and physical activity habits. The same number and frequency of meetings (in-person or virtual) and methods of registration of bedtime/wake-up times will be used as in the sleep extension group. These meetings will be educational in nature and focus on general well-being and informing the families about the home registrations of e.g., sleep and dietary intake.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
BMI Z-score	BMI (in kg/m^2) will be calculated from weight and height (secondary outcomes), and the age- and sex-specific BMI Z-score (in units of standard deviation from the reference population mean) will be computed using international (WHO) data	Assessed at months 0, 3 and 9
Learning ability: skill learning	Skill learning ability will be measured as motor memory assessed as 24h retention after skill practice - I.e. total within and between session effect (range: from "low" = 0 to "high" = 100, unitless)	Assessed at months 0 and 3
Learning ability: Explicit memory	Explicit memory assessed as 24h retention after word list memory encoding - I.e. total within and between session effect. Number of correctly recalled words in a 2-minute standardized task (range: from 0 to 20)	Assessed at months 0 and 3

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body fat percent	Body fat in % of total body mass (total fat mass divided by total body weight) will be measured by a whole-body dual-energy X-ray absorptiometry (DXA) scan	Assessed at months 0, 3 and 9
Total fat mass (FM)	Body FM (in grams) will be measured by a whole-body dual-energy X-ray absorptiometry (DXA) scan	Assessed at months 0, 3 and 9
Total lean mass (LM)	Body LM (in grams) will be measured by a whole-body dual-energy X-ray absorptiometry (DXA) scan	Assessed at months 0, 3 and 9
Bone mineral content (BMC)	BMC (in grams) will be measured by a whole-body dual-energy X-ray absorptiometry (DXA) scan	Assessed at months 0, 3 and 9
Bone mineral density (BMD)	Areal BMD (in grams/cm^2) will be measured by a whole-body dual-energy X-ray absorptiometry (DXA) scan	Assessed at months 0, 3 and 9
Dietary energy intake	Daily energy intake (in kcal/day) will be assessed with a three-day 24-hour recall interview on www.myfood24.org (daily averages will be computed)	Assessed at months 0, 3 and 9
Dietary protein, carbohydrate, fiber, and fat intakes	Macronutrient intakes (in grams/day) will be assessed with a three-day 24-hour recall interview on www.myfood24.org (daily averages will be computed)	Assessed at months 0, 3 and 9
Subjective hunger	Subjective level of hunger (range: from "very hungry" = 1 to "not hungry at all" = 5) in the fasting state and at 1 and 2 hours after a standardized breakfast will be measured by using an image-based visual analog scale (VAS)	Assessed at months 0 and 3
Physical activity (PA) time: total PA and MVPA	The time (in min/day) spent being physically active regardless of intensity (total PA) and the time (in min/day) spent on moderate-to-vigorous-physical-activities (MVPA) will be measured for 7 consecutive days (daily averages will be computed) using a wrist-worn triaxial accelerometer	Assessed at months 0, 1.5,3 and 9
Resting metabolic rate (RMR)	RMR (in kcal/day) will be measured with indirect calorimetry (canopy mode) the morning after an overnight fast (at least 8 hours)	Assessed at months 0 and 3
Thermic effect of food (TEF)	TEF (in kcal) will be computed as the incremental area under the curve (above RMR) for postprandial energy expenditure (measured by indirect calorimetry) for 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Weight	Body mass (in kg) will be measured on a digital scale to the nearest 0.1 kg	Assessed at months 0, 3 and 9
Height	Stature (in cm) will be measured using a wall-mounted stadiometer to the nearest 0.1 cm	Assessed at months 0, 3 and 9
Total energy expenditure (TEE)	TEE (in kcal/day) will be measured by using the doubly labelled water method (8 urine samples over 2 weeks)	Assessed at months 0 and 3
Cognitive functions: Sustained attention	Performance in neuropsychological assessment of sustained attention ability assessed as errors during a sustained test procedure, CANTAB test battery.	Assessed at months 0, 3 and 9
Cognitive functions: Spatial working memory	Performance in neuropsychological assessment of spatial working memory assessed as errors and strategy during the test procedure (Cambridge Neuropsychological Test Automated Battery, Cambridge cognition, UK).	Assessed at months 0, 3 and 9
Cognitive functions: Inhibitory control	Performance in neuropsychological assessment of inhibitory control assessed as errors during the test procedure (Modified Eriksen Flanker test, Psychology Software Tools, US) and Cambridge Neuropsychological Test Automated Battery, Cambridge cognition, UK)	Assessed at months 0, 3 and 9
Cognitive functions: Cognitive flexibility	Performance in neuropsychological assessment of cognitive flexibility assessed as errors during the test procedure (Cambridge Neuropsychological Test Automated Battery, Cambridge cognition, UK)	Assessed at months 0, 3 and 9
School performance: mathematics performance	Mathematics proficiency will be measured by Hogrefe math test	Assessed at months 0, 3 and 9
School performance: reading comprehension	Danish reading proficiency will be measured by Hogrefe reading comprehension test	Assessed at months 0, 3 and 9
Neurophysiological Measurement 1 - ERP Amplitude	EEG activity measured as the event-related potential (ERP) amplitude during the modified Eriksen Flanker Test	Assessed at months 0 and 3
Neurophysiological Measurement 2 - Cortical activity during skill learning	Cortical activity during skill learning will be measured as EEG power	Assessed at months 0 and 3
Neurophysiological Measurement 3 - Muscle activity during skill learning	Muscle activity during skill learning will be measured as electromyography amplitude	Assessed at months 0 and 3
Neurophysiological Measurement 4 - corticocortical functional connectivity	Corticocortical functional connectivity will be measured as functional coupling in EEG (scale 0-1)	Assessed at months 0 and 3
Neurophysiological Measurement 5 - corticomuscular connectivity	Corticomuscular connectivity will be measured as functional coupling between EEG and EMG during skill learning (0-1)	Assessed at months 0 and 3
Eating window	The parents will be asked to note on a checklist when their children start and finish eating on each registration day to estimate the duration of the daily eating window.	Assessed at months 0, 3 and 9.

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Fasting and postprandial glucose concentration	The concentration of glucose (in mmol/L) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial insulin concentration	The concentration of insulin (in pmol/L) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial total, HDL and LDL cholesterol concentrations	The concentrations of total, HDL and LDL cholesterol (in mmol/L) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial triglyceride concentration	The concentration of triglyceride (in mmol/L) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial C-reactive protein concentration	The concentration of CRP (in mg/L) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial tumor necrosis factor alpha concentration	The concentration of TNFa (in ng/L) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial ghrelin concentration	The concentration of ghrelin (in pg/mL) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial leptin concentration	The concentration of leptin (in ng/mL) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial glucagon like peptide 1 concentration	The concentration of GLP1 (in pg/mL) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial peptide YY concentration	The concentration of PYY (in pg/mL) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial cholecystokinin concentration	The concentration of CKK (in pg/mL) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Fasting and postprandial interleukin 6 concentration	The concentration of IL6 (in ng/L) will be measured in blood during fasting and at 2 hours after consuming a standardized breakfast	Assessed at months 0 and 3
Cognitive functions: processing speed	Performance in neuropsychological assessment of processing speed as choice reaction time, CANTAB test battery.	Assessed at months 0, 3 and 9
Health-related quality of life: child-reported	The total summary score of health-related quality of life (from 50 to 250), and sub-scale scores (from 10 to 50) of physical well-being, psychological well-being, autonomy and parent relation, peers and social support, and school environment, will be assessed by KIDSCREEN 27 questionnaire	Assessed at months 0, 3 and 9
Health-related quality of life: parent-reported	The Health Related Quality of Life score (from 0 to 100), Physical Health Summary score (from 0 to 100) and Psychosocial Health summary score (from 0 to 100) will be assessed by the Pediatric Quality of Life inventory (PedsQL)-Parent report (separate version for 6-7 y and 8-9 years olds)	Assessed at months 0, 3 and 9
Mental health: parent-reported	The total difficulties score (from 0 to 40) of the Strengths and Difficulties Questionnaire, as well as sub-scale scores (from 0 to 10) of emotional symptoms, conduct problems, hyperactivity/inattention, relationship problems and prosocial behavior	Assessed at months 0, 3 and 9
Parental Stress Scale: parent-reported	Perceived parental stress (from 18 to 90) will be assessed by the Parental Stress Scale questionnaire	Assessed at months 0, 3 and 9
Perceived Stress Scale: child-reported	Perceived child stress score (from 1 to 39) will be assessed by the PSS-C questionnaire	Assessed at months 0, 3 and 9
Demographics: income	Income level (stepwise increasing from level 1 to 7) will be reported by the parents on a demographics questionnaire	Assessed at month 0
Demographics: education	Education level (stepwise increasing from level 1 to 8) will be reported by the parents on a demographics questionnaire	Assessed at month 0
Wakefulness	Wakefulness (score from "very awake" = 1 to "sleeping" = 8) assessed by Standford Sleepiness Scale	Assessed at months 0, 3 and 9
Handedness	Handedness preference (right or left) will be assessed by asking the children "Which hand do you use to write and draw?" do to determine dominant hand	Assessed at month 0
Fine Motor Control	Fine motor control will be assessed by the pegboard test (score in number of pins placed correctly)	Assessed at months 0, 3 and 9
Muscle strength	Muscular strength of the handgrip will be measured by a handgrip dynamometer (in Newton)	Assessed at months 0, 3 and 9
Brain myelination	Indices of myelination in grey and white matter are estimated using R1 obtained from an MP2RAGE MRI-sequence	Assessed at months 0 and 3
Brain structural connectivity and microstructure	Grey and white matter microstructure will be examined using diffusion-weighted imaging	Assessed at months 0 and 3
Brain functional connectivity	Functional connectivity will be measured using resting-state function MRI (fMRI)	Assessed at months 0 and 3
Vital signs: blood pressure	Systolic and diastolic blood pressure (in mmHg) will be measured at rest by using a automatic sphygmomanometer	Assessed at months 0, 3 and 9
Vital signs: heart rate	Heart rate (in beats per minute, bpm) will be measured at rest by using an automatic sphygmomanometer	Assessed at months 0, 3 and 9
Vital signs: temperature	Body (skin) temperature (in degrees Celsius) will be measured telemetrically in the ear	Assessed at months 0, 3 and 9
Sleep quality: self-reported sleep duration	Sleep duration (hour/night) will be measured by the Scandinavian Sleep Questionnaire (Child and parent-reported).	Assessed at months 0, 3 and 9
Sleep quality: self-reported latency	Latency (minutes) will be measured by the Scandinavian Sleep Questionnaire (Child and parent-reported)	Assessed at months 0, 3 and 9
Sleep quality: self-reported awakenings	Awakenings (number/night) will be measured by the Scandinavian Sleep Questionnaire (Child and parent-reported).	Assessed at months 0, 3 and 9
Sleep quality: self-reported tiredness/sleepiness	Tiredness/sleepiness during the day (yes/no) will be measured by the Scandinavian Sleep Questionnaire (Child and parent-reported).	Assessed at months 0, 3 and 9
Sleep quality and architecture: Sleep stages	Sleep stages (distribution of sleep stages in minutes and percentages of total sleep time) will be measured by polysomnography through a one night sleep period.	Assessed at months 0 and 3
Sleep quality and architecture: sleep duration	Total sleep time (minutes) will be measured by polysomnography through a one night sleep period.	Assessed at months 0 and 3
Sleep quality and architecture: sleep latency	Sleep latency (minutes) will be measured by polysomnography through a one night sleep period.	Assessed at months 0 and 3
Sleep quality and architecture: awakenings	Awakenings (number) will be measured by polysomnography through a one night sleep period.	Assessed at months 0 and 3
Sleep quality and architecture: arousals	Arousals (number per hour) will be measured by polysomnography through a one night sleep period.	Assessed at months 0 and 3
Sleep: duration	Sleep duration (in minutes per night) will be measured by using a wrist-worn triaxial accelerometer for 7 consecutive days (the average will be computed).	Assessed at months 0, 1.5,3 and 9
Sleep: movements	Movements (number) will be measured by using a wrist-worn triaxial accelerometer for 7 consecutive days (the average will be computed).	Assessed at months 0, 1.5,3 and 9
Sleep: awakenings	Awakenings (number) will be measured by using a wrist-worn triaxial accelerometer for 7 consecutive days (the average will be computed).	Assessed at months 0, 1.5,3 and 9
Brain structure: cortical thickness	Cortical thickness (mm) will be measured by a T1-weighted MR-image (MP2RAGE).	Assessed at months 0 and 3
Brain structure: volume	Volume (mm3) will be measured by a T1-weighted MR-image (MP2RAGE).	Assessed at months 0 and 3
Brain structure: Surface	Surface area (mm2) will be measured by a T1-weighted MR-image (MP2RAGE).	Assessed at months 0 and 3
Brain structure: volumes of subcortical grey matter structures	Volumes (mm3) of subcortical grey matter structures will be measured by a T1-weighted MR-image (MP2RAGE).	Assessed at months 0 and 3
Fasting concentration of peripheral blood mononuclear cells.	The concentration of isolated blood mononuclear cells will be measured in blood in fasting state.	Assessed at months 0 and 3
Fasting concentration of sex hormones	The concentration of sex hormones will be measured in blood during fasting.	Assessed at months 0 and 3
Puberty stage	Puberty stage will be evaluated by a standardized questionnaire completed by the parents that assesses the child's puberty stage according to the Tanner's stage classification method.	Assessed at months 0, 3 and 9.

Collaborators and Investigators

• Sponsor: University of Copenhagen
• Collaborators: University of Southern Denmark; Danish Research Centre for Magnetic Resonance; Faculty of Health, Medicine and Life Sciences, Maastricht University; Center for Obesity Research & Education, Temple University; Novo Nordisk Foundation (NNF)
• Investigators: Principal Investigator: Faidon Magkos, PhD, University of Copenhagen, Department of Nutrition, Exercise and Sports

Study record dates

Study Major Dates

• Study Start (Actual): August 13, 2024
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2028

Study Registration Dates

• First Submitted: August 10, 2023
• First Submitted That Met QC Criteria: March 25, 2024
• First Posted (Actual): April 2, 2024

Study Record Updates

• Last Update Posted (Actual): November 25, 2025
• Last Update Submitted That Met QC Criteria: November 19, 2025
• Last Verified: January 1, 2025

More Information

Terms related to this study

• Keywords: Memory; Well-being; Sleep quality; Sleep duration; Cognitive Function; Energy Intake; Overweight and Obesity; Child Development and Behavior; Learning Ability
• Additional Relevant MeSH Terms: Nervous System Diseases; Mental Disorders; Nutrition Disorders; Overnutrition; Body Weight; Sleep Wake Disorders; Sleep Disorders, Intrinsic; Dyssomnias; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Overweight; Obesity; Sleep Initiation and Maintenance Disorders; Pediatric Obesity; Behavior; Child Behavior
• Other Study ID Numbers: M2S; H-23063352 (Other Identifier: Vek.dk)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No