Acute Effects of Sitting and Physical Activity on Brain Health

Study Overview
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Brief Summary
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The specific aim of this study is to understand how a working day composed of prolonged sitting, sitting regularly interrupted by light aerobic exercise or resistance exercise affects an important mechanism underpinning healthy brain functions, namely cerebral blood flow. It is primarily focused on investigating these effects in ecologically valid conditions, i.e. activity patterns that closely resemble a typical day at the office.

Detailed Description
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The study will be a controlled crossover experimental trial with three conditions involving 13 adult participants aged between 40 and 60 years. Each participant will complete each of the three experimental conditions, separated by a washout period of minimum four days. As well, physical activity behaviours and sleep the day/night before the test day will be measured. The first visit will be a familiarization session. On the second, third, and fourth visits, participants will undergo three different standardized 3-hour interventions in a randomized order. Before and immediately after the three-hour interventions, blood pressure, augmentation index, and cerebral hemodynamic response of the prefrontal cortex during standardized cognitive tasks (1,2, and 3-back tests) will be measured. Additionally, saliva samples will be collected the morning of the test day and before and after the interventions, blood glucose will be assessed continuously during the trial, and fitness will be measured at the familiarization visit.

Official Title
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Acute Effects of Sitting and Physical Activity on Cerebrovascular Circulation Among Adults

Conditions
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Healthy Adults

Intervention / Treatment
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* Behavioral: Prolonged sitting with social break
* Behavioral: Prolonged sitting with walk break
* Behavioral: Prolonged sitting with simple resistance activities


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: - Has a BMI under 35kg/m2 Exclusion Criteria: Has diabetes, epilepsy, or circulatory conditions Has experienced heart failure, stroke, or myocardial infarction Takes treatment for high blood pressure, sleep disorders, depression, or psychosis

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 60 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 with social break<br> | Behavioral: Prolonged sitting with social break<br>* Participants are required to sit for three hours (reading is permitted), with a toilet break in between. Every thirty minutes participants will have a short social break. Test day begins at 7:30 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 walk break<br> | Behavioral: Prolonged sitting with walk break<br>* Participants are required to sit for three hours (reading is permitted), with a toilet break in between. Every thirty minutes participants will have a physical activity break, where they will perform a brisk walk for about three minutes on a treadmill at a predetermined speed and grade based on the fitness test performed during the familiarization session. Test day begins at 7:30 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 simple resistance activities<br> | Behavioral: Prolonged sitting with simple resistance activities<br>* Participants are required to sit for three hours (reading is permitted), with a toilet break in between. Every thirty 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 7:30 with pretest measures, followed by the intervention at about 9:00, 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 3 hour intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Augmentation index | as a measure of arterial stiffness | before to after 3 hour intervention | 
| Blood glucose levels |  | during the 3 hour intervention | 
| Cortisol |  | before to after 3 hour intervention | 
| Mood | measured with the 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) | before to after 3 hour intervention | 
| Sleepiness | measured with Karolinska Sleepiness Questionnaire; goes from 1 (extremely alert) to 9 (extremely sleepy) | before to after 3 hour intervention | 
| Cognitive performance | nback cognitive test (time and accuracy) | before to after 3 hour intervention | 
| Alertness | measured with a Visual Analogue Scale (VAS) | before to after 3 hour intervention |