Isometric Exercise for Hypertension

Not Applicable

Recruiting

Brief Summary: Background: Isometric resistance exercises (IREs) have great potential to improve blood pressure (BP) control.

Methods: This is a pilot randomized controlled trial that will involve 50 patients with hypertension (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. All patients will be followed up for 24 weeks. 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 rate of recruitment. Secondary outcomes will include BP parameters from 24-hour ambulatory BP monitoring

Recruitment & Eligibility

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
pregnancy/breastfeeding
active malignancy

Arm && Interventions

Group	Intervention	Description
isometric exercise	wall squat	wall squat 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)
passive stretching	passive stretching	A frequency-matched (3x/week) and time-matched (\~14 minutes each session) passive static stretching exercise will be used

Primary Outcome Measures

Name	Time	Method
rate of recruitment	through study completion, an average of 1 year	number of people recruited per month

Secondary Outcome Measures

Name	Time	Method
Blood pressure parameters	24-week after recruitment	24-hour, daytime and nighttime blood pressure from 24-hour ambulatory systolic and diastolic blood pressure measurement
flow-mediated velocity (FMD)	24-week after recruitment	FMD will be performed using a high-resolution linear artery transducer couple with a software (FMD suite, Quipu, Italy) that automatically detect and measure the brachial artery diameter and will be performed according to international guidelines
Carotid-femoral pulse wave velocity	24-week after recruitment	analysed by applanation tonometry using SphygmoCor (AtCor Medical Pty Ltd) with the accompanying SphygmoCor Software Suite (SphygmoCor System)

Locations (1): School of public health and primary care
🇭🇰
Hong Kong, Hong Kong

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