Isometric Resistance Exercise for Hypertension

Official title

Effectiveness and Mechanisms of Isometric Resistance Exercise to Reduce Blood Pressure in a Chinese Population: a Randomized-controlled Trial

Overview

Background: Isometric resistance exercises (IREs) have great potential to improve blood pressure (BP) control. However, the effectiveness of IREs in reducing HT is still unknown because their hypotensive effects have not been detected using ambulatory BP measurements (ABPM), which are the current standard for BP measurement. Methods: This first adequately-powered RCT will involve 390 patients with HT who do not meet the current physical activity guidelines defined by the World Health Organization. Participants will be randomly assigned in a 1:1 ratio using stratified and blocked randomization to either the IRE (wall squat) group or stretching exercise (active control) group. A well-structured, widely accepted, and validated 24-week wall squat program (2 minutes per exercise, 2 minutes of rest between sets, and 3 sessions per week) will be implemented, as it has been commonly used in previous research. Adherence to the program will be monitored using smartwatches, and regular contact with patients through social media will help ensure adherence. All patients will be followed up for 1 year to investigate the long-term effects of IREs on BP. Control group will receive exact same treatment except that IRE is replaced by frequency-matched and time-matched stretching exercise. The primary outcome measure will be systolic daytime ABPM BP at 24 weeks. Secondary outcome measures will include other BP and ABPM parameters at 12 weeks, 24weeks and 1year, cfPWV at baseline, 24 weeks and 1year, and FMD at baseline and 24weeks. Safety data will be collected and reported.

Interventions

• Behavioral isometric wall exercise
  Each exercise session will contain 4 sets of 2-minute wall squat isometric holds with 2 minutes of rest between each set (approximately 14 minutes per session in total), and a total of 3 sessions will be arranged every week (with ideally 48 h between exercises)
• Behavioral passive stretching
  A frequency-matched (3x/week) and time-matched (\~14 minutes each session) passive static stretching exercise will be used

Primary outcome measures

• daytime systolic blood pressure (BP) assessed via ambulatory blood pressure monitoring (ABPM) [Time frame: 24-week after recruitment (immediate post-intervention)]

Secondary outcome measures (3)

• Other blood pressure indices [Time frame: 24-week, 1 year]
• Carotid-femoral pulse wave velocity [Time frame: 24-week after recruitment (immediate post-intervention), 1 year]
• flow-mediated dilation of brachial artery (FMD) [Time frame: 24-week after recruitment (immediate post-intervention), 1 year]

Eligibility criteria

Inclusion criteria

• a suboptimal daytime SBP of >135-160 mmHg on a 24-h ABPM
• reported no regular physical activity or less than that recommended for adults by the World Health Organization (e.g. <150 minutes of moderate-intensity aerobic exercise per week)
• on stable doses of anti-HT medication(s) for ≥4 weeks if the patient is receiving drug treatments;
• agree for no drug changes during the intervention period (24 weeks);

Exclusion criteria

• cannot provide informed consent
• unwillingness to repeat ABPM
• relative contraindications to ABPM (i.e. diagnosed atrial fibrillation, nighttime workers, occupational drivers, or patients with bleeding tendencies)
• severe osteoarthritis pending knee replacement surgery
• known secondary HT
• use of ≥3 anti-HT medications at maximum doses or ≥4 anti-HT medications
• SBP or DBP are >160 mmHg or >100 mmHg, respectively, on ABPM at baseline or at 12 weeks follow-up to ensure safety
• pregnancy/breastfeeding
• active malignancy

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Double blind

Primary purpose

Treatment

Study locations

Hong Kong · 2 centers

• Lek Yuen General Outpatient Clinic — Hong Kong
• School of public health and primary care — Hong Kong

Publications

• Ng SN, Yip BH, Sit RW, Woo KS, Wang S, Cohen DD, Lopez-Jaramillo P, Persu A, Tan GM, Cornelissen V, Pyun WB, Camafort BM, Wong SY, Lee EK. Effectiveness and mechanisms of isometric resistance exercise to reduce blood pressure in a Chinese population: study protocol for a randomized-controlled trial. Trials. 2026 Jun 3. doi: 10.1186/s13063-026-09798-x. Online ahead of print. PMID 42237351

Identifiers

NCT: NCT06510998 · 2022.618

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗