Unilateral and Bilateral Resistance Training in Hypertension

August 5, 2026 updated by: Ceyhun Topcuoglu, Hacettepe University

Comparison of the Effects of Unilateral and Bilateral Resistance Training on Heart Rate Variability, Muscle Strength, and Functional Capacity in Individuals With Hypertension: A Randomized Controlled Trial

Hypertension is associated with autonomic nervous system dysfunction, reduced muscle strength, and impaired functional capacity, all of which contribute to increased cardiovascular risk and decreased quality of life. Resistance training is recommended as a non-pharmacological intervention for hypertension; however, it remains unclear whether unilateral and bilateral resistance training produce different physiological adaptations, particularly regarding cardiac autonomic function.

This randomized controlled trial aims to compare the effects of unilateral and bilateral resistance training on heart rate variability (HRV), muscle strength, and functional capacity in adults with hypertension. Eligible participants aged 40-75 years with a confirmed diagnosis of hypertension will be randomly allocated to one of three groups: a unilateral resistance training group, a bilateral resistance training group, or a control group. Randomization will be performed using a computer-generated block randomization procedure with sex stratification to ensure balanced group allocation.

Participants in the two intervention groups will complete a supervised 12-week resistance training program, performed twice weekly at an intensity of 60-70% of one-repetition maximum (1RM). The unilateral training group will perform exercises using one limb at a time, whereas the bilateral training group will perform the same exercises simultaneously with both limbs. The control group will receive no structured exercise intervention during the study period but will receive general information regarding the benefits of physical activity.

Assessments will be conducted at baseline and after the 12-week intervention. The primary outcome will be heart rate variability measured using a Polar H10 heart rate sensor and Elite HRV software. Secondary outcomes will include peripheral muscle strength assessed by one-repetition maximum testing, functional capacity assessed using the Six-Minute Walk Test and the Glittre Activities of Daily Living Test, and blood pressure measured using a sphygmomanometer.

The findings of this study are expected to provide evidence regarding the optimal resistance training strategy for improving autonomic function and physical performance in individuals with hypertension, thereby supporting the development of safer and more individualized exercise prescriptions.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Hypertension is one of the leading modifiable risk factors for cardiovascular disease and is strongly associated with autonomic nervous system dysfunction. Increased sympathetic activity and reduced parasympathetic activity contribute to impaired cardiovascular regulation, which can be assessed non-invasively through heart rate variability (HRV). Reduced HRV has been associated with increased cardiovascular morbidity and mortality. In addition to autonomic dysfunction, individuals with hypertension frequently exhibit reduced muscle strength, impaired functional capacity, and limitations in daily physical activities.

Resistance training is widely recommended as a safe and effective non-pharmacological intervention for hypertension because it improves blood pressure control, muscular fitness, and overall physical function. Although both unilateral and bilateral resistance training are commonly prescribed, their physiological effects may differ. Unilateral resistance exercises generally involve a smaller active muscle mass, potentially resulting in lower cardiovascular stress while maintaining local muscular adaptations. In contrast, bilateral resistance exercises recruit a larger muscle mass and may induce greater cardiovascular and hemodynamic responses. Despite these theoretical differences, evidence directly comparing their effects on cardiac autonomic regulation in individuals with hypertension remains limited.

The primary objective of this randomized controlled trial is to compare the effects of unilateral and bilateral resistance training on cardiac autonomic function assessed by HRV in adults with hypertension. Secondary objectives include evaluating changes in peripheral muscle strength, functional capacity, activities of daily living, and blood pressure following a supervised resistance training program.

Adults aged 40 to 75 years with a physician-confirmed diagnosis of hypertension who are able to participate safely in resistance exercise will be recruited from Munzur University and Tunceli State Hospital. After providing written informed consent, eligible participants will be randomly assigned to one of three groups using a computer-generated block randomization procedure with sex stratification:

Unilateral Resistance Training Group Bilateral Resistance Training Group Control Group

Participants allocated to the intervention groups will complete a supervised 12-week resistance training program performed twice weekly. Exercise intensity will be prescribed at 60-70% of one-repetition maximum (1RM). Both intervention groups will perform the same resistance exercises, including leg press, knee extension, leg curl, seated row, and chest press. The unilateral group will perform each exercise separately with the right and left limbs, whereas the bilateral group will perform the exercises simultaneously using both limbs. Each exercise session will consist of 2-3 sets of 8-12 repetitions with at least one minute of rest between sets. Training loads will be progressively increased when participants are able to perform more than 20 repetitions with a perceived exertion below 3 on the Modified Borg Scale.

Participants in the control group will not receive supervised resistance training during the 12-week intervention period but will receive standardized education regarding the health benefits of regular physical activity. Following study completion, participants in the control group will be offered the exercise intervention if the training program is demonstrated to be beneficial.

Outcome assessments will be performed at baseline and after completion of the 12-week intervention. HRV will be measured using a Polar H10 heart rate sensor connected to the Elite HRV application. Measurements will be obtained before exercise, immediately after exercise, and during the recovery period. Time-domain variables, including RMSSD, SDNN, pNN50, and mean RR interval, as well as frequency-domain variables, including total power, LF power, HF power, LF/HF ratio, LF peak frequency, and HF peak frequency, will be analyzed.

Peripheral muscle strength will be evaluated using one-repetition maximum testing for leg press, knee extension, leg curl, seated row, and chest press. Functional capacity will be assessed using the Six-Minute Walk Test (6MWT), while functional performance in activities of daily living will be evaluated using the Glittre Activities of Daily Living Test (Glittre-ADL). Resting and exercise blood pressure will be measured using a validated sphygmomanometer.

The study hypothesis is that unilateral resistance training will produce improvements in HRV, muscle strength, and functional capacity comparable to or greater than bilateral resistance training while imposing lower cardiovascular stress. The findings are expected to provide evidence supporting individualized resistance exercise prescription for individuals with hypertension and contribute to the optimization of exercise-based cardiovascular rehabilitation programs.

Study Type

Interventional

Enrollment (Estimated)

54

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Adults aged 40 to 75 years.
  • Physician-confirmed diagnosis of hypertension.
  • Medically stable and able to safely participate in a supervised resistance training program.
  • Able to understand the study procedures and provide written informed consent.

Exclusion Criteria:

  • Presence of cardiovascular diseases other than hypertension.
  • Neurological disorders.
  • Psychiatric disorders.
  • Orthopedic conditions limiting participation in resistance exercise.
  • Any other systemic disease that may interfere with study participation.
  • Cognitive impairment or psychological conditions preventing completion of the assessments.
  • History of recent surgery or medical conditions contraindicating exercise.
  • Inability or unwillingness to comply with the study protocol.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Unilateral Resistance Training Group
Participants will receive a supervised unilateral resistance training program twice weekly for 12 weeks. Training intensity will be set at 60-70% of one-repetition maximum (1RM). Exercises will include leg press, knee extension, leg curl, seated row, and chest press, performed separately with the right and left limbs. Each session will consist of 2-3 sets of 8-12 repetitions with at least 1 minute of rest between sets. Training load will be progressively increased according to participants' performance and perceived exertion.
Other: Unilateral Resistance Training
Participants will complete a supervised unilateral resistance training program twice weekly for 12 weeks. Exercise intensity will be prescribed at 60-70% of one-repetition maximum (1RM). Exercises include leg press, knee extension, leg curl, seated row, and chest press performed separately with the right and left limbs. Each session consists of 2-3 sets of 8-12 repetitions with at least 1 minute of rest between sets. Training loads will be progressively increased based on participants' performance and perceived exertion using the Modified Borg Scale.
Experimental: Bilateral Resistance Training Group
Participants will receive a supervised bilateral resistance training program twice weekly for 12 weeks. Exercise intensity will be prescribed at 60-70% of one-repetition maximum (1RM). The training program will include leg press, knee extension, leg curl, seated row, and chest press performed simultaneously with both limbs. Each exercise will be completed for 2-3 sets of 8-12 repetitions with at least 1 minute of rest between sets. Training intensity will be progressively increased according to participants' performance and perceived exertion.
Other: Bilateral Resistance Training
Participants will complete a supervised bilateral resistance training program twice weekly for 12 weeks. Exercise intensity will be prescribed at 60-70% of one-repetition maximum (1RM). Exercises include leg press, knee extension, leg curl, seated row, and chest press performed simultaneously with both limbs. Each session consists of 2-3 sets of 8-12 repetitions with at least 1 minute of rest between sets. Training loads will be progressively increased according to participants' performance and perceived exertion using the Modified Borg Scale.
No Intervention: Control Group
Participants assigned to the control group will not receive supervised resistance training during the 12-week study period. They will receive standardized education regarding the health benefits of regular physical activity. After study completion, participants will be offered the exercise program if the intervention is shown to be beneficial.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Muscle Strength
Time Frame: Baseline and Week 12
Muscle strength will be assessed using one-repetition maximum (1RM) testing for leg press, knee extension, leg curl, seated row, and chest press exercises.
Baseline and Week 12
Functional Capacity
Time Frame: Baseline and Week 12
Functional capacity will be evaluated using the Six-Minute Walk Test (6MWT). Walking distance and physiological responses will be recorded before and after the intervention.
Baseline and Week 12
RMSSD
Time Frame: Baseline and Week 12
Change in the root mean square of successive differences (RMSSD) measured using heart rate variability analysis. RMSSD is reported in milliseconds (ms). Minimum value: 0 ms. There is no fixed maximum value. Higher values indicate greater parasympathetic activity and improved cardiac autonomic function (better outcome).
Baseline and Week 12
SDNN
Time Frame: Baseline and Week 12
Change in the standard deviation of normal-to-normal intervals (SDNN) measured using heart rate variability analysis. SDNN is reported in milliseconds (ms). Minimum value: 0 ms. There is no fixed maximum value. Higher values indicate greater overall heart rate variability and improved cardiac autonomic function (better outcome).
Baseline and Week 12
pNN50
Time Frame: Baseline and Week 12
Change in the percentage of successive normal-to-normal intervals differing by more than 50 ms (pNN50). The outcome is expressed as a percentage (%). Minimum value: 0%. Maximum value: 100%. Higher values indicate greater parasympathetic activity (better outcome).
Baseline and Week 12
Mean RR Interval
Time Frame: Baseline and Week 12
Change in mean RR interval measured using heart rate variability analysis. The outcome is expressed in milliseconds (ms). Minimum value: 0 ms. There is no fixed maximum value. Higher values generally indicate a lower resting heart rate and improved autonomic regulation (better outcome).
Baseline and Week 12
Total Power
Time Frame: Baseline and Week 12
Change in total power measured using heart rate variability analysis. The outcome is expressed in milliseconds squared (ms²). Minimum value: 0 ms². There is no fixed maximum value. Higher values indicate greater overall heart rate variability (better outcome).
Baseline and Week 12
LF Power
Time Frame: Baseline and Week 12
Change in low-frequency (LF) power measured using heart rate variability analysis. The outcome is expressed in milliseconds squared (ms²). Minimum value: 0 ms². There is no fixed maximum value. Higher values generally indicate greater autonomic modulation.
Baseline and Week 12
HF Power
Time Frame: Baseline and Week 12
Change in high-frequency (HF) power measured using heart rate variability analysis. The outcome is expressed in milliseconds squared (ms²). Minimum value: 0 ms². There is no fixed maximum value. Higher values indicate greater parasympathetic activity (better outcome).
Baseline and Week 12
LF Peak
Time Frame: Baseline and Week 12
Change in low-frequency peak (LF Peak) measured using heart rate variability analysis. The outcome is expressed in hertz (Hz). Minimum value: 0 Hz. There is no fixed maximum value.
Baseline and Week 12
HF Peak
Time Frame: Baseline and Week 12
Change in high-frequency peak (HF Peak) measured using heart rate variability analysis. The outcome is expressed in hertz (Hz). Minimum value: 0 Hz. There is no fixed maximum value.
Baseline and Week 12

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Activities of Daily Living
Time Frame: Baseline and Week 12
Change in activities of daily living performance assessed using the Glittre Activities of Daily Living (Glittre ADL) Test. The outcome is the total time required to complete the Glittre ADL Test, measured in seconds (s). Minimum value: 0 seconds. There is no fixed maximum value. Lower completion times indicate better functional performance in activities of daily living (better outcome), whereas higher completion times indicate poorer functional performance (worse outcome).
Baseline and Week 12
Blood Pressure
Time Frame: Baseline and Week 12
Systolic and diastolic blood pressure will be measured using a validated sphygmomanometer before exercise, immediately after exercise, and 30 minutes after exercise during the baseline and post-intervention assessments.
Baseline and Week 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hacettepe University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 22, 2026

Primary Completion (Estimated)

September 25, 2026

Study Completion (Estimated)

October 1, 2026

Study Registration Dates

First Submitted

August 2, 2026

First Submitted That Met QC Criteria

August 5, 2026

First Posted (Actual)

August 7, 2026

Study Record Updates

Last Update Posted (Actual)

August 7, 2026

Last Update Submitted That Met QC Criteria

August 5, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026/8-21

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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