Sedentary Behaviour, Physical Activity Patterns, and Cardiometabolic Health (SPARC)

From Sitting to Moving: How Physical Activity Patterns Can Reduce Sedentary Behaviour and Support Cardiometabolic Health

According to the World Health Organization (WHO), chronic diseases are a major global public health concern and the leading cause of mortality worldwide. In the absence of evidence-based actions, the global annual deaths from chronic diseases are projected to rise to 55 million deaths in 2030, accompanied by a substantial increase in socio-economic costs. In this context, the WHO identifies type 2 diabetes mellitus (T2DM) and cardiovascular diseases (CVD) as key chronic conditions of concern related to cardiometabolic health.

Both sedentary behaviour (SB) and physical inactivity have been recognised as interdependent risk factors for the development of T2DM and CVD. SB refers to any waking behaviour, characterised by a low energy expenditure, while being in a sitting or reclining posture, whereas physical inactivity denotes insufficient levels (<150 min per week,) of moderate-to-vigorous physical activity (MVPA). Studies using objective measures have demonstrated that on average Western adults spend 8-12h in SB per day, of which the majority is spent in prolonged sedentary bouts (lasting ≥30 min). In addition, up to 30% of adults worldwide are physically inactive, with higher levels of inactivity in high-income countries. Within this context, it has become evident that excessive prolonged SB, often in combination with physical inactivity, negatively impacts cardiometabolic health, contributing to insulin resistance, increased adiposity, poor lipid profiles and endothelial dysfunction. Given their detrimental effects on T2DM and CVD, strategies aimed at reducing SB and promoting physical activity (PA) warrant further investigation.

Reducing and regularly interrupting SB, even with low-intensity PA, alongside sufficient MVPA, is crucial for maintaining a healthy cardiometabolic profile. Reflecting this, the WHO guidelines advise individuals to engage in 150-300 minutes of moderate-intensity physical activity, 75-150 minutes of vigorous-intensity physical activity, or an equivalent combination each week. Notably, the 2020 WHO guidelines also included recommendations on SB for the first time, emphasizing the importance of limiting sedentary time. The WHO states that replacing SB with physical activity of any intensity can yield health benefits. However, these recommendations remain non-prescriptive and somewhat vague, primarily due to a lack of robust scientific evidence on the optimal frequency, intensity, and duration of PA needed to interrupt sedentary time. The absence of specific guidelines on prolonged SB reflects this evidence gap. To support policy development, well-designed randomised controlled trials are needed to evaluate effective and practical strategies for reducing sedentary time.

So far, the short term cardiometabolic health effects of SB interruptions have been investigated by our research group, laboratory studies of collaborators and other international researchers, demonstrating that; 1) more frequent SB interruptions especially affect glucose metabolism and insulin sensitivity; 2) higher intensity interruptions are associated with cardioprotective adaptations and; 3) longer durations of SB interruptions positively affect lipid metabolism. However, because under real-world conditions frequency, intensity and duration of SB interruptions usually interact, their combined effects on cardiometabolic health need further investigation. Many studies already compared the isolated effects of different SB interruption patterns with respect to frequency, duration and intensity on cardiometabolic health. However, the combined effects of these different approaches matched for energy expenditure are not clear yet. We therefore perform a balanced cross-over study in which the efficacy of distinct activity patterns on cardiometabolic health insulin sensitivity and vascular function) will be compared to a sedentary control condition.

Study Overview

• Status: Not yet recruiting
• Conditions: Healthy Adult Participants
• Intervention / Treatment: Behavioral: Continuous moderate intensity physical activity; Behavioral: Light-intensity physical activity breaks; Behavioral: High-intensity physical activity breaks

• Study Type: Interventional
• Enrollment (Estimated): 48
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Wouter Franssen, PhD; Phone Number: +32(0)11 29 21 29; Email: wouter.franssen@uhasselt.be
• Study Contact Backup: Name: Bert Op 't Eijnde, PhD; Email: bert.opteijnde@uhasselt.be

Study Locations

• Belgium
  • Limburg
    • Diepenbeek, Limburg, Belgium, 3590
      • Hasselt University
      • Contact: Bert Op 't Eijnde, PhD; Email: bert.opteijnde@uhasselt.be
      • Contact: Wouter Franssen, PhD; Email: wouter.franssen@uhasselt.be

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adults aged 40-70 years
• Sedentary (>9 hours per day)
• < 3 exercise sessions per week

Exclusion Criteria:

• Pregnancy or intend to become pregnant
• Any known contra-indications for physical activity
• >14 alcohol consumptions per week for women and >20 alcohol consumptions per week for men
• Involved in a weight reduction program with an energy restriction diet during the study period
• No consistent body weight over the past month
• Diagnosed with any known cardiometabolic health-related disease

Study Plan

How is the study designed?

Design Details

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

Number of Arms

6

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Control; Prolonged sitting for 6 hours
Experimental: Continuous moderate intensity physical activity; One continuous physical activity bout of moderate intensity will be performed during the 6 hour testing day.	Behavioral: Continuous moderate intensity physical activity; One continuous physical activity bout of moderate intensity will be performed during the 6 hour testing day.
Experimental: Continuous moderate intensity physical activity + light-intensity physical activity breaks; One continuous physical activity bout of moderate intensity will be combined with light-intensity physical activity breaks every 30 minutes during the 6 hour testing day.	Behavioral: Continuous moderate intensity physical activity; One continuous physical activity bout of moderate intensity will be performed during the 6 hour testing day.; Behavioral: Light-intensity physical activity breaks; Light-intensity physical activity breaks every 30 minutes during the 6 hour testing day.
Experimental: Continuous moderate intensity physical activity + high-intensity physical activity breaks; One continuous physical activity bout of moderate intensity will be combined with high-intensity physical activity breaks every 30 minutes during the 6 hour testing day.	Behavioral: Continuous moderate intensity physical activity; One continuous physical activity bout of moderate intensity will be performed during the 6 hour testing day.; Behavioral: High-intensity physical activity breaks; High-intensity physical activity breaks every 30 minutes during the 6 hour testing day.
Experimental: Light-intensity physical activity breaks; Prolonged sitting will be interrupted by light-intensity physical activity breaks every 30 minutes during the 6-hour testing day.	Behavioral: Light-intensity physical activity breaks; Light-intensity physical activity breaks every 30 minutes during the 6 hour testing day.
Experimental: High-intensity physical activity breaks; Prolonged sitting will be interrupted by high-intensity physical activity breaks every 30 minutes during the 6-hour testing day.	Behavioral: High-intensity physical activity breaks; High-intensity physical activity breaks every 30 minutes during the 6 hour testing day.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total and incremental area under the curve of postprandial insulin response	Insulin concentrations will be assessed in serum samples at nine time points over the 6-hour testing period. Postprandial responses will be quantified as the area under the curve (AUC) across the six-hour period.	Blood samples will be collected at 0, 30, 60, 120, 180, 210, 240, 300, and 360 minutes during the 6-hour testing day.
Vascular endothelial function	Vascular endothelial function will be assessed by flow-mediated dilation (FMD) according to published guidelines. These measurements take place at 8 a.m. 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%).	FMD measurement will be performed at the start (08:30 a.m.) and after 6 hours (2:30 p.m.) of the testing day.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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 (Metalyzer IIIb) until volitional exhaustion.	Baseline measurement
Sedentary time	Sedentary time will be quantified using the activPAL3™ activity monitor.	Measured for 7 consecutive days after the screening visit
Body mass index	Body mass index (BMI; kg/m²) is calculated from weight and height measurements (weight/height²).	Baseline measurement
Moderate-to-vigorous physical activity	Moderate-to-vigorous physical activity will be quantified using the activPAL3™ activity monitor.	Measured for 7 consecutive days after the screening visit
Body weight	Body weight (in underwear) is determined using a digital-balanced weighting scale to the nearest 0.1kg.	Baseline measurement
High-density lipoprotein cholesterol concentration	High-density lipoprotein cholesterol concentration will be measured in fasting plasma samples	Blood samples will be taken at the beginning of the testing day (8 a.m.).
Total cholesterol concentration	Total cholesterol concentration will be measured in fasting plasma samples	Blood samples will be taken at the beginning of the testing day (8 a.m.).
Total and incremental area under the curve of postprandial glucose response	Glucose concentrations will be assessed in plasma samples at nine time points over the 6-hour testing period. Postprandial responses will be quantified as the area under the curve (AUC) across the six-hour period.	Blood samples will be collected at 0, 30, 60, 120, 180, 210, 240, 300, and 360 minutes during the 6-hour testing day.
Total and incremental area under the curve of postprandial insulin response	Triglyceride concentrations will be assessed in plasma samples at nine time points over the 6-hour testing period. Postprandial responses will be quantified as the area under the curve (AUC) across the six-hour period.	Blood samples will be collected at 0, 30, 60, 120, 180, 210, 240, 300, and 360 minutes during the 6-hour testing day.
Peak heart rate	Peak heart rate assessed during cardiopulmonary exercise testing	Baseline measurement
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.	Blood pressure will be measured during the screening visit, and hourly at 0, 60, 120, 180, 240, 300, and 360 minutes during the 6-hour testing day.
Body fat percentage	Percentage body fat will be evaluated using Dual Energy X-ray Absorptiometry.	Baseline measurement
Low-density lipoprotein cholesterol concentration	Low-density lipoprotein cholesterol concentration will be measured in fasting plasma samples	Blood samples will be taken at the beginning of the testing day (8 a.m.).
Waist circumference		Baseline measurement

Collaborators and Investigators

• Sponsor: Hasselt University

Study record dates

Study Major Dates

• Study Start (Estimated): March 1, 2026
• Primary Completion (Estimated): June 1, 2028
• Study Completion (Estimated): June 1, 2028

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 10, 2026
• First Posted (Actual): February 18, 2026

Study Record Updates

• Last Update Posted (Actual): February 18, 2026
• Last Update Submitted That Met QC Criteria: February 10, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Physical Activity; Intensity; Frequency; Duration; Cardiometabolic health
• Additional Relevant MeSH Terms: Behavior; Motor Activity
• Other Study ID Numbers: CME2025/100

Drug and device information, study documents

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