Polarized Aerobic Training and Vascular Adaptations in Apparently Healthy Individuals

NCT07665632 | Recruiting

• 1 other identifier: ACT-ON-CHRONIC
• Study Type: interventional
• Target: 30
• Locations: 1 country
• Sites: 1

Brief Summary

This randomized controlled trial will investigate the effects of a 6-week polarized aerobic training intervention on vascular and cardiorespiratory function in apparently healthy sedentary adults aged 30-50 years. Polarized training is characterized by a high proportion of low-intensity aerobic exercise combined with a smaller volume of high-intensity interval exercise, potentially providing complementary haemodynamic and physiological stimuli that support vascular adaptations and cardiovascular health. Although polarized training has been extensively studied in athletic populations, its effects on vascular function in sedentary adults remain insufficiently understood. Thirty participants will be randomly assigned in a 1:1 ratio to either a supervised polarized aerobic training group or a non-exercising control group. The intervention will consist of a 6-week supervised cycle ergometer training program performed three times per week and prescribed according to individual ventilatory thresholds obtained during cardiopulmonary exercise testing. Training sessions will combine low-to-moderate-intensity continuous exercise and high-intensity interval exercise. Participants allocated to the control group will maintain their habitual sedentary lifestyle throughout the study period. The primary outcome will be endothelial function assessed by brachial artery flow-mediated dilation. Secondary outcomes will include arterial stiffness assessed by pulse wave velocity, central haemodynamics, microvascular function, cardiorespiratory fitness, skeletal muscle function, pulmonary function, respiratory muscle strength, and circulating biomarkers related to vascular health. Outcome measures will be assessed at baseline and after completion of the 6-week intervention period. The findings of this study may improve understanding of vascular and systemic adaptations to polarized aerobic training and help inform future exercise-based strategies for cardiovascular risk reduction in apparently healthy sedentary adults.

Conditions

Sedentary Lifestyle

Keywords

Polarized training; Vascular function; Flow-mediated dilation; Pulse wave velocity; Randomized controlled trial

Outcome Measures

Primary Outcomes (6)

• Brachial artery flow-mediated dilation (FMD)

  Endothelial function will be assessed using brachial artery flow-mediated dilation (FMD) measured by high-resolution ultrasound following a standardized ischemia-reperfusion protocol. FMD will be expressed as the relative (%) increase in brachial artery diameter following cuff release compared with baseline diameter.

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Flow-mediated slowing (FMS)

  Flow-mediated slowing (FMS, %) will be assessed using pulse wave velocity deceleration after occlusion of the brachial artery with an oscillometric device (Vicorder, Skidmore Medical, United Kingdom).

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Carotid-femoral pulse wave velocity

  Carotid-femoral pulse wave velocity will be assessed using an oscillometric device (Vicorder, Skidmore Medical, United Kingdom) and reported in m/s.

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Brachial-radial pulse wave velocity

  Brachial-radial pulse wave velocity will be assessed using an oscillometric device (Vicorder, Skidmore Medical, United Kingdom) and reported in m/s

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Femoral-ankle pulse wave velocity

  Femoral-ankle pulse wave velocity will be assessed using an oscillometric device (Vicorder, Skidmore Medical, United Kingdom) and reported in m/s.

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Maximal oxygen uptake (VO2max)

  Maximal oxygen uptake will be assessed during cardiopulmonary exercise testing on a cycle ergometer with respiratory gas analysis and reported in mL/kg/min.

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

Secondary Outcomes (13)

• Aortic pulse pressure (AOPP)

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Augmentation index

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Muscle tissue reoxygenation slope (microvascular reactivity)

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Skeletal muscle stiffness

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

• Forced vital capacity (FVC)

  Baseline and post-intervention (week 6; at least 72 hours after the final exercise session)

Study Arms (2)

Polarized Aerobic Training

EXPERIMENTAL

Participants will undergo a 6-week supervised polarized aerobic training programme performed three times weekly on a cycle ergometer, combining low-to-moderate-intensity continuous training and high-intensity interval training prescribed according to ventilatory thresholds obtained during cardiopulmonary exercise testing.

Behavioral: Polarized Aerobic Training

Non-Exercising Control

NO INTERVENTION

Participants will maintain their habitual sedentary lifestyle throughout the 6-week intervention period and will refrain from initiating structured exercise training. Habitual physical activity patterns will be monitored throughout the study period.

Interventions

Polarized Aerobic Training BEHAVIORAL

Participants will undergo a 6-week supervised polarized aerobic training programme performed three times weekly on a cycle ergometer. The intervention will combine low-to-moderate-intensity continuous training and high-intensity interval training prescribed according to individual ventilatory thresholds determined during cardiopulmonary exercise testing. The weekly structure will include two high-intensity interval sessions and one continuous aerobic training session, thereby creating a polarized intensity distribution characterized by a predominance of low-intensity exercise and limited exposure to the moderate-intensity domain. Exercise intensity will be individualized using heart rate and power output targets, and all sessions will be supervised by trained personnel.

Polarized Aerobic Training

Eligibility Criteria

• Age: 30 Years - 50 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• Men and women aged 30-50 years
• Apparently healthy individuals without diagnosed cardiovascular, metabolic, or renal disease
• Sedentary lifestyle verified using the Global Physical Activity Questionnaire (GPAQ) and current physical activity classification criteria
• Ambulatory blood pressure values within the normotensive range (\<140 mmHg systolic and \<90 mmHg diastolic)
• Body mass index (BMI) \<30 kg/m²
• No regular participation in structured exercise training

You may not qualify if:

• Ambulatory blood pressure values ≥140 mmHg systolic and/or ≥90 mmHg diastolic
• Moderate or high physical activity level according to the Global Physical Activity Questionnaire (GPAQ)
• Diagnosed chronic cardiovascular, metabolic, renal, respiratory, or other systemic disease
• Use of prescribed medication influencing cardiovascular or metabolic function
• Musculoskeletal injury of the lower extremities within the previous six months
• Menopause
• Absence of a regular menstrual cycle
• Pregnancy
• Current smoking or tobacco use

Sponsors & Collaborators

• University of Ljubljana: lead

Study Sites (1)

University of Ljubljana, Faculty of sport

Ljubljana, 1000, Slovenia

RECRUITING

MeSH Terms

Conditions

Sedentary Behavior

Condition Hierarchy (Ancestors)

Behavior

Study Officials

• Armin Paravlić, PhD

  University of Ljubljana

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Gašper Tunšek, MSc

CONTACT

+38651302949; gasper.turnsek@fsp.uni-lj.si

Armin Paravlić, PhD

CONTACT

+386015207840; armin.paravlic@fsp.uni-lj.si

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Outcome assessors will be blinded to group allocation whenever possible.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: Parallel-group assessor-blinded randomized controlled trial with a supervised exercise intervention group and a non-exercising control group.

Study Record Dates

• First Submitted: May 7, 2026
• First Posted: June 24, 2026
• Study Start: May 25, 2026
• Primary Completion (Estimated): November 20, 2027
• Study Completion (Estimated): December 20, 2027
• Last Updated: June 24, 2026

Record last verified: 2026-06

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL
• Time Frame: The data and supporting materials will become available following publication of the primary study results and are expected to remain accessible through the institutional repository of the University of Ljubljana.
• Access Criteria: De-identified data and study protocol will be accessible to researchers and the broader scientific community through the institutional repository of the University of Ljubljana. Data will be available for scientifically valid research purposes without restrictions.

Locations

SL (1)