Activity Breaks for Brain Health in Adolescents

Study Overview
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Brief Summary
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The main aim for this study is to investigate to what extent physical activity of moderate or low intensity, relative to prolonged inactivity, may acutely alter neural activity-related prefrontal cortex oxygenated hemoglobin during a cognitive demanding task in 13- 15 year-old adolescents. The study is primarily focused on investigating these effects in ecologically valid conditions, i.e. activity patterns that closely resemble a typical day in school and using activity modes that are suitable in a school setting.

Detailed Description
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The study will be a controlled crossover experimental trial with three conditions. Each participant will complete each of the three experimental conditions, separated by a washout period of minimum four days. Physical activity behaviours and sleep will be monitored the day/night before each test day. The first visit will be a familiarization session for the collection of demographic data, fitness testing, and acquaintance with experimental procedures. On the second, third, and fourth visits, participants will undergo three different standardized 80-minutes interventions in a randomized order. Before and immediately after the 80-minutes interventions, blood pressure, augmentation index, and cerebral hemodynamic response of the prefrontal cortex during standardized cognitive tasks (nback test) will be measured. Additionally, saliva samples will be collected the morning of the test day, and before and after the interventions.

Official Title
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Acute Effects From Prolonged Inactivity and Physical Activity Interventions on Cortical Blood Flow and Arterials Stiffness in School-aged Adolescents.

Conditions
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Healthy Adolescents

Intervention / Treatment
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* Behavioral: Prolonged sitting (social breaks)
* Behavioral: Prolonged sitting with step-up exercise break
* Behavioral: Prolonged sitting with simple resistance activity breaks


Participation Criteria
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Eligibility Criteria
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Exclusion Criteria: Ongoing medication that can affect central circulation or brain circulation Ongoing infection Inability to apprehend information about the study or to perform the tests

Ages Eligible for Study
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Minimum Age: 13 Years
Maximum Age: 14 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Prolonged sitting (social breaks)<br> | Behavioral: Prolonged sitting (social breaks)<br>* Participants are required to sit for 80 minutes doing schoolwork, with a toilet break in between. Every twenty minutes participants will have a short social break. Test day begins at 8:00 with pretest measures, followed by the intervention at about 9:00, which will end around 12:00, with subsequent posttest measures.<br>|
| Experimental: Prolonged sitting with step-up exercise break<br> | Behavioral: Prolonged sitting with step-up exercise break<br>* Participants are required to sit for 80 minutes doing schoolwork, with a toilet break in between. Every twenty minutes participants will have a physical activity break, where they will perform a simple moderate-intensity step-up exercise for three minutes at a predetermined pace. Test day begins at 8:00 with pretest measures, followed by the intervention at about 9:30, which will end around 12:00, with subsequent posttest measures.<br>|
| Experimental: Prolonged sitting with simple resistance activity breaks<br> | Behavioral: Prolonged sitting with simple resistance activity breaks<br>* Participants are required to sit for 80 minutes doing schoolwork, with a toilet break in between. Every twenty minutes participants will have a physical activity break, where they will perform simple resistance activities following a video for about three minutes. Test day begins at 8:00 with pretest measures, followed by the intervention at about 9:30, which will end around 12:00, with subsequent posttest measures.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in cerebral blood flow | Oxygenated and deoxygenated hemoglobin concentration changes measured with functional near-infrared spectroscopy | before to after 80 minutes intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cognitive performance | nback cognitive test (time and accuracy) | before and after 80 minutes intervention | 
| Augmentation index | measure of arterial stiffness | before and after 80 minutes intervention | 
| Cortisol | measured from saliva | morning; before and after 80 minutes intervention | 
| Mood | Positive and Negative Affect Schedule (PANAS) comprised of 20 affect states (10 positive and 10 negative), each affect state scored on a scale going from 1 (very slightly or not at all) to 5 (extremely) | at the beginning of the day; before and after 80 minutes intervention | 
| Sleepiness | Karolinska Sleepiness Questionnaire; goes from 1 (extremely alert) to 9 (extremely sleepy) | at the beginning of the day; before and after 80 minutes intervention | 
| Alertness | 100mm Visual Analogue Scale (VAS); range: 'not at all' to 'completely alert' | at the beginning of the day; before and after 80 minutes intervention |