Interrupting Sitting With High Intensity Exercise on Vascular Function in Adolescents Before and After a Mixed Meal

University of Exeter

Status: Terminated

Conditions: Endothelial Dysfunction; Cardiovascular Risk Factor

Treatments: Behavioral: Interrupting 3 hours of prolonged sitting with high intensity interval exercise; Behavioral: 3 hours of prolonged sitting

Study type: Interventional

Funder types: Other

Identifiers

NCT04337385

191204/B/04

Details and patient eligibility

About

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.

Full 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.

Enrollment: 6 patients

Sex: All

Ages: 12 to 15 years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Basic Science

Allocation: Non-Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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6 participants in 2 patient groups

3 hours of Prolonged Sitting

Experimental group

Description:

Participants will sit continuously for three hours before receiving a mixed meal challenge.

Treatment:

Behavioral: 3 hours of prolonged sitting

3 hours of interrupted sitting with hourly HIIE

Experimental group

Description:

Participants will have their three hour sitting period interrupted with high intensity interval cycling exercise (HIIE) at 30, 90 and 150 minutes into the intervention. In each exercise bout, they will cycle at 90% peak power for 3 x 60 second periods with 75 seconds of recovery in-between.

Treatment:

Behavioral: Interrupting 3 hours of prolonged sitting with high intensity interval exercise