Combining Physical Activity and Sedentary Interventions to Improve Cardiometabolic Health (CAS)

Many adults spend a large part of their day sitting, especially at work. Long periods of sitting and not moving enough can increase the risk of health problems such as heart disease and type 2 diabetes. This risk is even higher in people who have early warning signs like being overweight, having high blood pressure, or problems with blood sugar. Together, these problems are called metabolic syndrome.

The goal of this study is to find out whether combining regular exercise with reducing sitting time during the day can improve heart and metabolic health more than exercise alone.

About 40 adults between 18 and 65 years old who work mainly at a desk and sit for more than 9 hours a day will take part. All participants will first continue their normal daily routine for two weeks. After that, they will be randomly placed into one of two groups for eight weeks:

Exercise group: Participants will follow the World Health Organization guidelines for physical activity. This includes two sessions of moderate exercise each week (such as brisk walking or cycling) and one session of more intense exercise each week.

Exercise plus less sitting group: Participants will do the same exercise program, but they will also be encouraged to sit less during the workday. They will be asked to stand more, use sit-stand desks if possible, and avoid sitting for longer than one hour at a time.

Participants will visit the research center three times for health tests. These tests include blood samples to look at blood sugar, insulin, and fats in the blood, measurements of blood pressure and heart function, body composition scans, fitness tests, and questionnaires about sleep, diet, and quality of life. They will also wear activity monitors to measure how much they sit, stand, and move.

The main outcome is how the body handles sugar (insulin sensitivity). The researchers hope to learn whether sitting less, in addition to exercising, leads to better improvements in heart and metabolic health. The results may help develop better lifestyle advice to prevent heart disease and diabetes in people with desk jobs.

Study Overview

• Status: Active, not recruiting
• Conditions: Insulin Resistance; Cardiometabolic Risk Factors; Sedentary Behaviors
• Intervention / Treatment: Behavioral: WHO physical activity guideline; Behavioral: Sedentary behaviour reduction at the workplace

• Study Type: Interventional
• Enrollment (Estimated): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Belgium
  • Limburg
    • Diepenbeek, Limburg, Belgium, 3590
      • Univeristeit Hasselt

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Age 18 to 65 years
• Profession where most of the time is spent sitting.
• Not regularly physically active (>3 trainings per week in the last three months)
• Sedentary (on average >9 hours per day spent sedentary on a working day)
• Written informed consent to participate in the study.

Exclusion Criteria:

• Pregnancy.
• Consumption of more than 20 units of alcohol per week.
• Medical conditions that limit physical activity.
• Specific diet (e.g. low-carbohydrate or calorie-restricted).
• Unstable body weight in the past month.
• Participation in another study that could potentially affect your blood parameters in the past month.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control arm (2 weeks); All participants will follow a two-week period where no intervention is administered.
Active Comparator: PA group (8 weeks); After the control period without intervention, one halve of the participants is randomised to the PA group where participants are encouraged to adhere to WHO physical activity guidelines during 8 weeks.	Behavioral: WHO physical activity guideline; Individualised Physical Activity Plan (8 weeks): • Two weekly sessions of moderate-intensity physical activity (MIPA): Frequency: 2 sessions per week. Unsupervised. Duration: Initially 40 minutes per session, increasing to 50 minutes by week 4. Type of Activity: Participants can select from brisk walking, cycling, swimming, or elliptical training. Intensity: 40-60% of maximal oxygen consumption, monitored with wearable heart rate devices. • One weekly session of vigorous-intensity physical activity (VIPA): Frequency: 1 session per week. Supervised or predetermined. Duration: Initially 20 minutes per session, increasing to 30 minutes by week 4. Type of Activity: Options include running, high-intensity interval training (HIIT), or fast cycling. Intensity: 60-90% of maximal oxygen consumption, tracked with heart rate devices. • Weekly check-ins will allow adjustments based on individual feedback and progress.
Experimental: PA-SB group (8 weeks); After the control period without intervention, one halve of the participants is randomised to the PA-SB group where participants are encouraged to adhere to WHO physical activity guidelines. In addition, sedentary time at the workplace is reduced. The duration of this intervention is 8 weeks.	Behavioral: WHO physical activity guideline; Individualised Physical Activity Plan (8 weeks): • Two weekly sessions of moderate-intensity physical activity (MIPA): Frequency: 2 sessions per week. Unsupervised. Duration: Initially 40 minutes per session, increasing to 50 minutes by week 4. Type of Activity: Participants can select from brisk walking, cycling, swimming, or elliptical training. Intensity: 40-60% of maximal oxygen consumption, monitored with wearable heart rate devices. • One weekly session of vigorous-intensity physical activity (VIPA): Frequency: 1 session per week. Supervised or predetermined. Duration: Initially 20 minutes per session, increasing to 30 minutes by week 4. Type of Activity: Options include running, high-intensity interval training (HIIT), or fast cycling. Intensity: 60-90% of maximal oxygen consumption, tracked with heart rate devices. • Weekly check-ins will allow adjustments based on individual feedback and progress.; Behavioral: Sedentary behaviour reduction at the workplace; Participants will be encouraged to replace seated work with standing work and engage in light physical activity breaks. • Workplace Integration Strategies: Participants working in an office setting will be provided with adjustable sit-stand desks where possible. • Active Breaks and Movement Interventions: Participants will be prompted to take short (2min) active breaks after prolonged periods of sedentary behaviour. Break activities will include standing, stretching, or light movement such as walking.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Homeostatic model assessment for insulin resistance (HOMA-IR)	The HOMA-IR is calculated from the fasting insulin and glucose concentration.	From enrollment to the end of the intervention at 8 weeks.
Whole-body insulin sensitivity index (ISI)	An oral glucose tolerance test will be performed for assessment of whole body insulin sensitivity using the whole-body insulin sensitivity index (ISI). The ISI is calculated from both insulin and glucose concentrations.	From enrollment to the end of the intervention at 8 weeks
Area under the curve of insulin concentrations	An oral glucose tolerance test will be performed for assessment of whole body insulin sensitivity by calculation of the area under the curve of insulin concentrations.	From enrollment to the end of the intervention at 8 weeks
Insulinogenic index	An oral glucose tolerance test will be performed for assessment of beta cell function by calculation of the insulinogenic index. The insulinogenic index is calculated from both insulin and glucose concentrations.	From enrollment to the end of the intervention at 8 weeks.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Body composition	Body composition is evaluated by Dual-energy X-ray absorptiometry. Fat mass (in kg), lean body mass (in kg), body fat percentage (in %) and visceral adipose tissue (in grams) will be derived from the Dual-energy X-ray absorptiometry.	From enrollment to the end of the intervention at 8 weeks.
Cardiorespiratory Fitness	Cardiorespiratory fitness will be measured as peak oxygen consumption (V̇O2peak) using a graded cardiopulmonary exercise test (CPET) on a bike with pulmonary gas exchange analysis (Jaeger Oxycon®) until volitional exhaustion.	From enrollment to the end of the intervention at 8 weeks.
Area under the curve of glucose concentrations	An oral glucose tolerance test will be performed for assessment of whole body insulin sensitivity by calculation of the area under the curve of glucose concentrations.	From enrollment to the end of the intervention at 8 weeks
Steps per day	Physical activity will be quantified using the activPAL3™ activity monitor.	From enrollment to the end of the intervention at 8 weeks. For one week during the first four weeks of the intervention. For one week during the last four weeks of the intervention.
Sitting time	Sedentary behaviour will be quantified using the activPAL3™ activity monitor.	From enrollment to the end of the intervention at 8 weeks. For one week during the first four weeks of the intervention. For one week during the last four weeks of the intervention.
Moderate to vigorous physical activity	Physical activity will be quantified using the activPAL3™ activity monitor.	From enrollment to the end of the intervention at 8 weeks. For one week during the first four weeks of the intervention. For one week during the last four weeks of the intervention.
Light intensity physical activity	Physical activity will be quantified using the activPAL3™ activity monitor.	From enrollment to the end of the intervention at 8 weeks. For one week during the first four weeks of the intervention. For one week during the last four weeks of the intervention.
Sleep	Physical activity will be quantified using the activPAL3™ activity monitor.	From enrollment to the end of the intervention at 8 weeks. For one week during the first four weeks of the intervention. For one week during the last four weeks of the intervention.
Body weight	Body weight (in underwear) is determined using a digital-balanced weighting scale to the nearest 0.1kg	From enrollment to the end of the intervention at 8 weeks
Height	Body height is measured to the nearest 0.1cm using a wall-mounted Harpenden stadiometer, with participants barefoot	From enrollment to the end of the intervention at 8 weeks.
Body mass index	Body mass index (BMI; kg/m²) is calculated from weight and height measurements (weight/height²).	From enrollment to the end of the intervention at 8 weeks
Waist and hip circumference	Waist and hip circumferences will be measured to the nearest 0.1 cm using a flexible metric measuring tape with participants barefoot (in underwear) in standing position. Waist circumference is measured at the midpoint between the lower rib margin and the top of the iliac crest. Hip circumference is measured at the widest circumference of the hip at the level of the greater trochanter. Waist-to-hip ratio is calculated by dividing waist circumference (cm) by hip circumference (cm). Waist-to-height ratio is calculated by dividing waist circumference (cm) by height (cm).	From enrollment to the end of the intervention at 8 weeks
Blood pressure	After an initial resting period of 10 min with participants in a supine position in a quiet room with constant temperature (21°C), systolic and diastolic blood pressure (BP; in mmHg) will be measured at least 3 times at 2-min intervals until BP is stable using an electronic sphygmomanometer (Omron®) from the left arm and documented as the mean value of the three final measurements.	From enrollment to the end of the intervention at 8 weeks
Vascular endothelial function	Vascular function will be assessed by FMD according to published guidelines. These measurements take place at 9h and involve doppler ultrasound imaging of the superficial femoral artery. A cuff will be placed on the right lower leg, and the superficial femoral artery is imaged longitudinally. FMD will be measured at baseline and after a 5-min occlusion phase (reactive hyperaemia response). FMD will be quantified as the percentage difference between peak and baseline diameter (FMD%).	From enrollment to the end of the intervention at 8 weeks
Cardiac autonomic function	Cardiac autonomic function will be operationalized as heart rate variability by means of continuous beat-to-beat heart rate signal measurements. time domain and frequency domain analysis of the R-R intervals will be performed	From enrollment to the end of the intervention at 8 weeks
Concentration of glucose	Blood analysis	From enrollment to the end of the intervention at 8 weeks
Concentration of insulin	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of total cholesterol	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of Low-Density Lipoprotein cholesterol	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of High-Density Lipoprotein cholesterol	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of triglycerides	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of apolipoproteins	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of CRP	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of Interleukin 6 (IL-6)	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Concentration of interleukin 1 (IL-1)	Blood analysis	From enrollment to the end of the intervention at 8 weeks.
Sleep quality	Sleep quality over a period of one month will be assessed with the Pittsburgh sleep quality index (PSQI) which is a self-administered questionnaire consisting of 19 items that is reliable and valid to assess sleep problems.	From enrollment to the end of the intervention at 8 weeks.
Food intake	Habitual dietary intake is assessed using a validated food frequency questionnaire (FFQ). In addition, participants will fill in a diary to evaluate dietary intake either with an app or on paper.	From enrollment to the end of the intervention at 8 weeks
Quality of life (QOL)	Health-related quality of life (HRQOL) was measured using the Euroqol 5-D questionnaire (EQ-5D). The EQ-5D is a widely used and validated generic instrument consisting of five dimensions: mobility, self- care, usual activities, pain/discomfort and anxiety/depression.	From enrollment to the end of the intervention at 8 weeks

Collaborators and Investigators

• Sponsor: Hasselt University
• Investigators: Principal Investigator: Jen Vanherle, MSc, Hasselt University

Study record dates

Study Major Dates

• Study Start (Actual): April 28, 2024
• Primary Completion (Estimated): February 1, 2026
• Study Completion (Estimated): February 1, 2026

Study Registration Dates

• First Submitted: December 22, 2025
• First Submitted That Met QC Criteria: January 14, 2026
• First Posted (Actual): January 23, 2026

Study Record Updates

• Last Update Posted (Actual): January 23, 2026
• Last Update Submitted That Met QC Criteria: January 14, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Exercise; Insulin resistance; Physical activity; Sedentary behaviour; Cardiometabolic health
• Additional Relevant MeSH Terms: Metabolic Diseases; Glucose Metabolism Disorders; Hyperinsulinism; Behavior; Nutritional and Metabolic Diseases; Insulin Resistance; Motor Activity; Sedentary Behavior
• Other Study ID Numbers: CME2024/069

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: In a restriced access depositry. Personal data is sensitive data and is thus protected in a restricted access repository. During the project these data will be pseudonymized and after completion of the project data will be anonymized and the pseudonymization key will be destroyed. Access can be granted by the primary investigator who holds the pseudonymization key in a restricted folder during the project.
• IPD Sharing Time Frame: After publication of the results, data will become available for a duration of 25 years.
• IPD Sharing Access Criteria: Access will be granted after motivated and reasonable request to the principal investigator.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP; ICF

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No