Clinical trial NCT04337385: Interrupting Sitting With High Intensity Exercise on Vascular Function in Adolescents Before and After a Mixed Meal
Official title: The Effect of Prolonged vs. Interrupted Sitting With High Intensity Interval Exercise on Lower Limb Vascular Function in Adolescents Before and After a Mixed Meal
Study type: INTERVENTIONAL
Overall status: TERMINATED
Phase: NA
Conditions: Cardiovascular Risk Factor
Endothelial Dysfunction
Keywords: Flow mediated dilation
Reactive hyperaemia
Endothelial function
Paediatrics
Physical inactivity
Lead sponsor: University of Exeter
Sponsor class: OTHER
Collaborators: name: University of British Columbia
First posted: 2020-04-07
Enrollment: 6
Sex: ALL
Minimum age (years): 12
Maximum age (years): 15
Standard ages: CHILD
Accepts healthy volunteers: yes
Allocation: NON_RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: BASIC_SCIENCE

Brief summary: This study aims to investigate the effect of interrupting a three hour bout of prolonged sitting with high intensity interval exercise on lower limb blood vessel function in adolescents before and after a mixed meal challenge.

Detailed description: Participants will be required to visit the laboratory on three separate occasions. The first of which will be a preliminary visit to collect anthropometric data (e.g. stature and body weight) and participants will complete a combined ramp-incremental and supra-maximal test to exhaustion on a cycle ergometer to determine the work rate for the exercise in the subsequent experimental visits.

For the two experimental visits, participants will arrive to the laboratory after an overnight fast and an activPAL accelerometer will be attached to the midline of the participants' thigh for the duration of the visit to quantity sitting time.

Lower limb macro and micro-vascular function will be assessed using a single protocol through flow mediated dilation of the popliteal artery and post-occlusive reactive hyperaemia in the capillaries of the calf. Participants will then either sit for three hours or have this three hour sitting period interrupted with high intensity interval cycling exercise at 30, 90 and 150 minutes. Vascular function will then be reassessed before participants will be given a mixed meal challenge (58.4 g fat and 53.4 g sugar) with a three hour postprandial period where the participants will remain seated for the duration. At the end of the postprandial period, vascular function will be reassessed.

Blood pressure, heart rate and calf circumference will be assessed hourly throughout the experimental day. In addition, capillary blood samples will be collected at baseline, pre meal and each hour during the postprandial period and assessed for changes in plasma glucose, triglyceride, cholesterol and insulin concentrations.

Participants will be transported to the toilet by wheelchair to limit the amount of walking undertaken during the sitting period and this activity will be quantified by the activPAL accelerometers.

Eligibility criteria: Inclusion Criteria:

* Male and female adolescents
* 12-15 years

Exclusion Criteria:

* Medications known to affect blood pressure, carbohydrate or fat metabolism
* Allergies to the test meal e.g. dairy or gluten
* Contraindications to exercise
* Individuals with special educational needs that mean they are unable to fully comprehend the demands of the study procedures

Primary outcomes:
measure: Popliteal macrovascular function
timeFrame: Before and after 3 hours of prolonged vs. interrupted sitting and after a subsequent 3 hour postprandial period
Secondary outcomes:
measure: Microvascular function in the capillaries of the calf
timeFrame: Before and after 3 hours of prolonged vs. interrupted sitting and after a subsequent 3 hour postprandial period
measure: Changes in plasma triglyceride concentration from a capillary sample
timeFrame: 6.5 hours
measure: Changes in plasma insulin concentration from a capillary sample
timeFrame: 6.5 hours
measure: Changes in plasma glucose concentration from a capillary sample
timeFrame: 6.5 hours
measure: Blood pressure
timeFrame: 6.5 hours
measure: Heart rate
timeFrame: 6.5 hours
measure: Calf circumference
timeFrame: 6.5 hours
measure: Physical activity prior to the experimental visits
timeFrame: 48 hours prior to each visit
measure: Sitting time during the experimental visits
timeFrame: 6 hours
Other outcomes:
measure: Participant Enjoyment During the High Intensity Interval Exercise
timeFrame: 3 hours
measure: Participant Enjoyment Post the High Intensity Interval Exercise
timeFrame: 3 hours
Locations:
city: Exeter
country: United Kingdom
facility: University of Exeter
state: Devon
Study officials:
affiliation: University of Exeter
name: Alan Barker, PhD
role: PRINCIPAL_INVESTIGATOR
References: