The Metabolic Effects of Breaks in Sedentary Time

Not Applicable

Completed

Interventions: Other: Sedentary
Other: Sedentary With Breaks and Physical Activity
Other: Sedentary With Breaks

Brief Summary: The purpose of this study is to determine whether acute bouts of sedentary behaviour (with or without breaks and/or structured physical activity) result in measurable changes in metabolic health in children and youth.

Detailed Description: North American children spend the majority of their waking hours engaging in sedentary behavior (e.g. sitting). Research in adults and animal models suggests that even short bouts of uninterrupted siting may result in acute changes increases in cardiometabolic risk, although to date no studies have investigated this relationship in children and youth. The purpose of this study is to assess the feasibility of a protocol which will expose participants aged 10-14 years to a full day of uninterrupted sitting, and to determine the impact of this protocol on markers of cardiometabolic risk (insulin, glucose, triglyceride, HDL-C and LDL-C) as well as subsequent food intake and physical activity. The impact of uninterrupted sitting will be compared to the impact of interrupted sitting, with and without the inclusion of moderate physical activity.

Recruitment & Eligibility

Inclusion Criteria

Exclusion Criteria

Overweight
Overt diabetes or heart disease (or taking medications to treat this conditions)
Being unambulatory or otherwise unable to perform the study protocol

Arm && Interventions

Group	Intervention	Description
Sedentary	Sedentary	In this condition, participants will engage in 8 hours of uninterrupted sedentary behaviour.
Sedentary With Breaks and Physical Activity	Sedentary With Breaks and Physical Activity	In this condition participants will engage in 8 hours of sitting, although the sitting will be interrupted every 20 minutes. During these interruptions participants will spend 2 minutes walking at an intensity equivalent to 30% of VO2peak. Participants will also engage in 20 minutes of structured physical activity at an intensity of 60% of VO2peak in both the morning and afternoon.
Sedentary With Breaks	Sedentary With Breaks	In this condition participants will engage in 8 hours of sitting, although the sitting will be interrupted every 20 minutes. During these interruptions participants will spend 2 minutes walking at an intensity equivalent to 30% of VO2peak.

Primary Outcome Measures

Name	Time	Method
Change in Insulin Net Incremental Area-Under-The-Curve (iAUC)	Baseline, 1.5, 3, 4.5, 6, and 7.5 hours	Insulin levels will be assessed multiple times throughout the day, and the resulting values will be used to calculate AUC.

Secondary Outcome Measures

Name	Time	Method
Change in Triglyceride Net Incremental Area-Under-The-Curve (iAUC)	Baseline, 1.5, 3, 4.5, 6, and 7.5 hours	Blood draws will be taken several times throughout the day, and the resulting values will be used to calculate AUC.
Change in Glucose Net Incremental Area-Under-The-Curve (iAUC)	Baseline, 1.5, 3, 4.5, 6, and 7.5 hours	Blood draws will occur throughout the day, and the resulting values will be used to calculate AUC.
Change in HDL-Cholesterol (HDL-C) Net Incremental Area-Under-The-Curve (iAUC)	Baseline, 1.5, 3, 4.5, 6, and 7.5 hours	Blood draws will occur throughout the day, and the resulting values will be used to calculate AUC.
Change in LDL-Cholesterol (LDL-C) Net Incremental Area-Under-The-Curve (iAUC)	Baseline, 1.5, 3, 4.5, 6, and 7.5 hours	Blood draws will occur throughout the day, and the resulting values will be used to calculate AUC.