Response Variability to Exercise

Not Applicable

Recruiting

• Conditions: Exercise; Cardiorespiratory Fitness
• Interventions: Behavioral: Low amount, high intensity exercise; Behavioral: Low amount, low intensity exercise; Behavioral: High amount, high intensity exercise

• Registration Number: NCT05496751
• Lead Sponsor: Robert Ross, PhD

Brief Summary

In this proposal, the investigators challenge the assumption that following the physical activity guidelines implies benefit for ALL adults, and that if benefit is not achieved in response to first line therapy, it will be by simply exercising more. Thus, for improving cardiorespiratory fitness and cardiometabolic risk factors, unanswered questions include: 1) To what extent, regardless of increasing exercise intensity or amount, is exercise not associated with benefit? Demonstration of a resistance to benefit through exercise in a substantial number of adults would be a novel and important finding, would counter the assumptions of many if not most health care practitioners, and could have immediate and direct application in all health care settings. 2) To what extent will non-responders to first line therapy (150 min/wk) be required to increase exercise intensity or amount to achieve benefit? 3) To what extent will failure to improve CRF segregate (be associate with) with cardiometabolic risk factors? The investigators propose that adults who remain exercise resistant for improvement in CRF and cardiometabolic risk despite increasing amount or intensity are at high risk of metabolic disease and consequently, are candidates for alternative treatment strategies.

Detailed Description

The trial has two objectives:

Primary objective: After 16 weeks of first line therapy (150 min/wk of MPA), does increasing exercise intensity or amount for 16 weeks improve cardiorespiratory fitness (CRF, VO2peak) deferentially depending on the CRF response at 16 weeks.

Secondary objective: Determine whether common cardiometabolic risk factors segregate/cluster with respect to variation in CRF to first line therapy in adults, and, whether clinically meaningful improvements in cardiometabolic risk factors segregate with improvement in CRF.

Study Timeline

• Study First Submitted: 2022-08-09
• Study First Submitted QC: 2022-08-09
• Study First Posted: 2022-08-11
• Study Start: 2022-09-30
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-17
• Last Update Posted: 2025-03-20
• Primary Completion: 2025-09-30
• Study Completion: 2025-09-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 200

Inclusion Criteria

• Sedentary lifestyle (planned physical activity for one day per week or less).
• Weight stable (± 2 kg) for 6 months prior to the beginning of the study.
• BMI between 20 and 40 kg/m2.

Exclusion Criteria

• Physical impairment which would make the intervention very difficult or unsafe according to doctor's advice.
• Diabetes, current smokers.
• Plan to move from the area in next 8 months.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Low amount, high intensity exercise	Low amount, high intensity exercise	exercise dose (amount and intensity) will be controlled.
Low amount, low intensity exercise	Low amount, low intensity exercise	exercise dose (amount and intensity) will be controlled.
High amount, high intensity exercise	High amount, high intensity exercise	exercise dose (amount and intensity) will be controlled.

Primary Outcome Measures

Name	Time	Method
Cardiorespiratory Fitness	Measured at baseline and every 4 weeks for 32 weeks.	Cardiorespiratory fitness will be determined using direct (open circuit spirometry) measures of oxygen consumption (expressed in L/min) obtained during a maximal treadmill test.

Secondary Outcome Measures

Name	Time	Method
Change in subcutaneous fat	Measured at baseline, 16 and 32 weeks.	Subcutaneous adiposity
Change in glucose	Measured at baseline, 16 and 32 weeks.	Fasting glucose (mmol/L)
Change in blood lipids	Measured at baseline, 16 and 32 weeks.]	Fasting LDL- and HDL-cholesterol (mmol/L)
Change in insulin	Measured at baseline, 16 and 32 weeks.]	fasting insulin (pmol/L)
Change in abdominal fat	Measured at baseline, 16 and 32 weeks.	Visceral adiposity
Change in lean body mass	Measured at baseline 16 and 32 weeks.	Lean mass
Change on body weight	Measured at baseline, 16 and 32 weeks.	Body weight
Change in triglycerides	Measured at baseline, 16 and 32 weeks.	fasting triglycerides (mmol/L)
Change in body fat	Measured at baseline, 16 and 32 weeks	Total adiposity
Change in obesity phenotype	Measured at baseline 16 and 32 weeks.	waist circumference

Trial Locations

Locations (1)

School of Kinesiology and Health Studies, Queen's University; 🇨🇦 Kingston, Ontario, Canada