Sedentary Behavior Breaks With Isometric Exercise in Cardiovascular Health Indicators

Study Overview
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Brief Summary
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The goal of this study is to analyze the chronic effects of sedentary behavior breaks using the leg extension isometric exercise in the cardiovascular health indicators of healthy adults exposed to prolonged time in the sitting position. The patients recruited will be randomized into two groups: leg extension isometric training (TIE) and control group (CG). The TIE group will perform 12 weeks of isometric training. The CG will be advised not to change their routine activities, especially diet and physical activities.In the pre and post-intervention periods cardiovascular measures will be obtained.

Detailed Description
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Long periods in sedentary behavior promote deterioration of vascular function, which is directly associated with the occurence of chronic noncommunicable diseases. In this context, the execution of interruptions in this behavior (breaks) is recommended. Studies have shown benefits of isometric training in vascular function, which could be useful to minimize the consequences of time spent in sedentary behavior. Thus, the goal of this study is to analyze the chronic effects of sedentary behavior breaks using leg extension isometric exercise in the cardiovascular health indicators of adults exposed to prolonged time in the sitting position. The target population of the study will consist of healthy subjects above 18 years of age of both genders. All subjects will be submitted to measurements of endothelial function, blood pressure and cardiac autonomic modulation. After these measurements, the subjects will be randomized into two groups: leg extension isometric training group (TIE) and control group (CG). After 12 weeks both groups will be submitted to the same measurements from pre-intervention.

Official Title
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Effects of Breaks of Sedentary Behavior With Isometric Exercise in Cardiovascular Health Indicators of Adults

Conditions
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Sedentary Behavior

Intervention / Treatment
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* Other: Leg Extension Isometric Training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: No diagnostic of cardiovascular diseases or diabetes Do not present high cardiovascular risk Do not participate in an exercise program in the previous six months Occupational activity that requires more than six hours of sitting time per day Do not be a smoker or make use of medications Exclusion Criteria: Adherence to the training sessions inferior to 85% Adherence to another supervised exercise program Change the characteristics of the occupational activities

Ages Eligible for Study
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Minimum Age: 18 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Randomized controlled trial and randomized crossover trial.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Leg Extension Isometric Training<br>Experimental group will perform leg extension isometric exercise. | Other: Leg Extension Isometric Training<br>* The leg extension isometric exercise will be performed tree times a week , in four 2 min bouts of isometric contraction, at a intensity of 30% of maximal voluntary contraction and an interval of two minutes between bouts.<br>|
| No Intervention: Control Group<br>Control group will be advised to maintain their work habits and not to change their routine activities, especially diet and physical activities. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in vascular function at 12 weeks | Vascular function will be measured before and after 12 weeks of intervention on the intervention and control groups by a bidimensional ultrasonography device with spectral Doppler and linear transducer. | Baseline and 12 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes from baseline in blood pressure at 12 weeks | Blood pressure will be measured before and after 12 weeks of intervention period on intervention and control group by an automatic blood pressure monitor (HEM-742, Omron Healthcare, Japan). | Baseline and 12 weeks | 
| Change from baseline in cardiac autonomic modulation at 12 weeks | Cardiac autonomic modulation will be measured before and after 12 weeks of intervention period on intervention and control group by heart rate monitor (Polar V800, Polar Electro, Finland). | Baseline and 12 weeks |