Effects of Interrupting Sedentary Behavior With High - or Low Intensity PA on CVD - and Cardiometabolic Riskfactors, and Cognitive Performance.

Effects of Interrupting Sedentary Behavior With High - or Low Intensity Physical Activity on Cardiovascular - and Cardiometabolic Riskfactors, and Cognitive Performance.

The knowledge gap on sedentary behavior and sedentary breaks includes whether detrimental effects of sedentary behavior can be fully attenuated by 1.) sedentary breaks 2.) physical activity or 3.) both combined. Specifically, when breaking sedentary time which physical activity pattern- and intensity modifies the negative effects of sedentary behavior on glucose- and lipid metabolism? This lack of quantitative evidence calls for prospective experimental studies investigating the physiological and biological impacts of sedentary behavior, as well as the effectiveness of different strategies to reduce sedentary time. Thus, quantifying effects of the intensity, frequency, volume of sedentary breaks and/or physical activity on predefined outcomes is of importance.

Aims:

Our primary aims are to investigate the effects of breaking up sedentary time on glucose- and lipid metabolism and thus examine whether physical activity intensity breaks during sedentary breaks matter. Specifically, the aims of the PhD-project are to provide knowledge on the following questions:

• How does high- or low physical activity intensity sedentary breaks acutely influence glucose- and lipid metabolism under iso-caloric conditions?

Study Overview

• Status: Completed
• Conditions: Physical Activity; Sedentary Behavior
• Intervention / Treatment: Behavioral: Sedentary behavior

Detailed Description

The participants will undergo 3 different trial conditions of which all are iso-caloric, but with different intensities when executing physical activity (PA) by treadmill walking corresponding to 25-30% or 80-85%, respectively, of their individual VO2max/peak values. PA intensities are estimated from the individual's pre-test. The trial-conditions are iso-caloric, and tailored to each individual's energy expenditure. This study has a is randomized cross-over design. If found eligible from step 1 and 2 in the inclusion process, participants will be invited to a final screening day in our lab. Eligible participants then consenting to joining the study will continue on to 3 trial days. Due to possible acute rise in insulin for up to 48 hours, a 5-14 day washout period between trials will be used to avoid carryover effects. In the washout periods between experimental conditions the participants will resume their habitual life activities and behaviors, i.e., diet and physical activity patterns. However, from visit 2, during washout the participants will wear accelerometers (ActiGraph GTX3+, Pensacola, FL) during waking hours to objectively measure sedentary time and physical activity for 7 consecutive days after each trial. Average sedentary time (hour/day) and time spent in , light-, moderate- and vigorous physical activity intensity (min/day) will be derived. During the main trial days, the participants may read or work on a personal computer during the sedentary time in the respective trial conditions. The sample size calculations with glucose as the primary outcome, are based on the study by Dunstan et al. (2012). They estimated that 19 paired observations were needed to secure a power of 0.90 in order to detect the smallest expected effect size between the interventions, when using a two-tailed test with a significance level of 5%. To account for the possibility of dropouts the sample size in the present project is set to recruit 30 participants, with 25 participants completing the trials, and thus planning for 80% power

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Norway
  • Oslo County
    • Oslo, Oslo County, Norway, 0806
      • Norwegian School of Sports Sciences

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 20 years to 45 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

Inclusion Criteria:

• Predominantly sedentary occupation.
• Physical activity: equal or less tham 150 minutes /week
• Nonobese. Central adiposity: Waist circumference equal or less than 102 cm for men and equal or less than < 88 cm for women. BMI < 30 km·m2

Exclusion Criteria:

• Shift-work
• Smoking
• Pregnancy
• Current use of medication, except from hormonal contraceptives.
• No presence of any co-morbidity (e.g. diabetes type 2, cardiovascular or cardiorespiratory disease, or other conditions known to affect carbohydrate and lipid metabolism - thyroid-, -liver or kidney).
• Systolic /diastolic resting blood pressure: > 140/90 mmHg
• Fasting blood glucose concentration: > 6.1 mmol/L
• Abnormal total cholesterol, LDL, LDL or triglyceride concentrations (> 50% above recommendations)

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Control trial; Sitting from 8 am until 3pm.	Behavioral: Sedentary behavior; Interrupting sitting with walking/jogging at either high -or low physical activity intensity.
Experimental: High intensity sedentary breaks; Physical activity on 80-85% of individual VO2max every hour. Modality: Hill walking/jogging on treadmill.	Behavioral: Sedentary behavior; Interrupting sitting with walking/jogging at either high -or low physical activity intensity.
Experimental: Low intensity sedentary breaks; Physical activity on 25-30% of individual VO2max every hour. Modality: Hill walking on treadmill.	Behavioral: Sedentary behavior; Interrupting sitting with walking/jogging at either high -or low physical activity intensity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total (tAUC)- and incremental areas under the curve (iAUC) for glucose	During each of the trial conditions blood samples will be taken in the fasted state in the morning and then every 30 minutes of the trials (total 420minutes) through a peripheral venous catheter. We will then calculate the iAUC for glucose for each of the trial condition and compare the different trial conditions with the control condition	The iAUC for glucose will be assessed during the procedure and consist of measures every 30 minute throughout the trial (420 minutes)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
tAUC and iAUC analyses for insulin	During each of the trial conditions blood samples will be taken in the fasted state in the morning and then every 30 minutes of the trials (total 420minutes) through a peripheral venous catheter. We will then calculate the iAUC for glucose for each of the trial condition and compare the different trial conditions with the control condition	The iAUC for the secondary outcomes will be assessed during the procedure and consist of measures every 30 minute throughout the trial (420 minutes)
tAUC and iAUC analyses for c-peptide	During each of the trial conditions blood samples will be taken in the fasted state in the morning and then every 30 minutes of the trials (total 420minutes) through a peripheral venous catheter. We will then calculate the iAUC for glucose for each of the trial condition and compare the different trial conditions with the control condition	The iAUC for the secondary outcomes will be assessed during the procedure and consist of measures every 30 minute throughout the trial (420 minutes)
tAUC and iAUC analyses for triglycerides	During each of the trial conditions blood samples will be taken in the fasted state in the morning and then every 30 minutes of the trials (total 420minutes) through a peripheral venous catheter. We will then calculate the iAUC for glucose for each of the trial condition and compare the different trial conditions with the control condition	The iAUC for the secondary outcomes will be assessed during the procedure and consist of measures every 30 minute throughout the trial (420 minutes)
tAUC and iAUC analyses for lipids	During each of the trial conditions blood samples will be taken in the fasted state in the morning and then every 30 minutes of the trials (total 420minutes) through a peripheral venous catheter. We will then calculate the iAUC for glucose for each of the trial condition and compare the different trial conditions with the control condition	The iAUC for the secondary outcomes will be assessed during the procedure and consist of measures every 30 minute throughout the trial (420 minutes)
Cognitive function and performance	Cognitive function tasks will be performed, and cognitive function will be assessed by Trail making test A and B, and Stroop-test.	The cognitive measures will be performed during the procedure (at approx 400 minutes)

Collaborators and Investigators

• Sponsor: Norwegian School of Sport Sciences
• Collaborators: The Research Council of Norway
• Investigators: Principal Investigator: Jostein Steene-Johennessen, Professor, Norwegian School of Sports Sciences

Study record dates

Study Major Dates

• Study Start (Actual): January 2, 2023
• Primary Completion (Actual): December 20, 2025
• Study Completion (Actual): December 20, 2025

Study Registration Dates

• First Submitted: January 6, 2023
• First Submitted That Met QC Criteria: January 23, 2023
• First Posted (Actual): February 2, 2023

Study Record Updates

• Last Update Posted (Actual): January 21, 2026
• Last Update Submitted That Met QC Criteria: January 17, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Physical Activity; Sitting; Cardiovascular; Sedentary behavior; Cardiometabolic
• Additional Relevant MeSH Terms: Behavior; Motor Activity; Sedentary Behavior
• Other Study ID Numbers: GENSED#2

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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