The goal of this clinical trial is to evaluate whether a short, supervised isometric handgrip exercise program is feasible and acceptable for older adults with elevated blood pressure or hypertension. It will also explore whether this type of exercise may improve blood pressure and cognitive function.
The main questions it aims to answer are:
* Is this handgrip exercise program practical and acceptable for older adults to participate in within a community exercise setting? * Does participation in the program lead to changes in blood pressure and cognitive function?
Researchers will compare two handgrip devices to determine whether the method of delivering the exercise influences feasibility and outcomes.
Participants will:
* Be randomly assigned to use one of two handgrip devices. * Complete supervised exercise sessions twice per week for 4 weeks. * Perform brief handgrip contractions at a set intensity during each session. * Complete blood pressure and cognitive assessments before and after the program.
65 years of age or older
Currently attending the Physical Activity Centre of Excellence at McMaster University
English speaking
Diagnosed with hypertension or elevated blood pressure
Current or prior participation in chronic isometric exercise
Unstable angina.
Uncontrolled hypertension
Uncontrolled heart failure and/or arrhythmias
Parallel
Zona Plus 4-Week Isometric Handgrip Exercise Intervention
Other interventionThis intervention consists of a supervised, low-dose isometric handgrip exercise program delivered over 4 weeks using the Zona Plus handgrip dynamometer. Participants will complete two sessions per week, each consisting of 4x2-minute isometric handgrip contractions performed at 30% of maximal voluntary contraction, with 1-minute rest periods between contractions. Contractions will be performed using alternating hands. All sessions will be conducted in person and supervised by trained research staff at the Physical Activity Centre of Excellence, and the intervention will completed before participants' existing exercise routines. Ratings of perceived exertion will be recorded following each contraction.
Squegg 4-Week Isometric Handgrip Exercise Intervention
Other interventionThis intervention consists of a supervised, low-dose isometric handgrip exercise program delivered over 4 weeks using the Squegg handgrip device. Participants will complete two sessions per week, each consisting of 4x2-minute isometric handgrip contractions performed at 30% of maximal voluntary contraction, with 1-minute rest periods between contractions. Contractions will be performed using alternating hands. All sessions will be conducted in person and supervised by trained research staff at the Physical Activity Centre of Excellence, and the intervention will completed before participants' existing exercise routines. Ratings of perceived exertion will be recorded following each contraction.
Change in Physical Activity Enjoyment Scale Score
Acceptability of the intervention will be assessed quantitatively using the change in Physical Activity Enjoyment Scale (PACES) score from baseline to post-intervention. The PACES is a self-report questionnaire consisting of 18 items rated on a 7-point Likert scale. Responses are summed to generate a total score ranging from 18 to 126, with higher positive change scores indicating greater enjoyment of physical activity and higher acceptability of the intervention.
Qualitative Acceptability (Interviews) of the Intervention
Acceptability of the intervention will be explored through semi-structured, one-on-one interviews conducted following post-intervention testing. Interviews will assess participants' experiences with the program, including perceived acceptability, enjoyment, burden, time commitment, ease of integration into existing routines, facilitators and barriers to adherence, sustainability, perceived effects, and overall impressions of the handgrip device. Interviews will be audio-recorded, transcribed, and analyzed using inductive thematic analysis to identify key themes related to participant experience and acceptability.
Recruitment Rate
Feasibility of recruitment will be assessed as the number of participants enrolled in the study over the recruitment period. Recruitment rate will be calculated as the average number of participants enrolled per month (participants/month).
Intervention Adherence (Session Attendance)
Adherence will be assessed as the proportion of prescribed intervention sessions attended by each participant. Session attendance (%) will be calculated as the number of attended sessions divided by the total number of prescribed sessions (8 sessions over 4 weeks), multiplied by 100. Higher percentages indicate greater adherence.
Change in Trail Making Test Part A Completion Time
Participants are asked to connect numbered circles in sequential order (1-2-3, etc.) as quickly as possible. This test assesses processing speed. Performance is measured as the total time in seconds (s) required to complete the task. Lower completion time indicates better performance.
Change in Trail Making Test Part B Completion Time
Participants are asked to alternate between numbers and letters in sequence (e.g., 1-A-2-B, etc.) while connecting circles as quickly as possible. This test assesses executive function and cognitive flexibility. Performance is measured as the total time in seconds (s) required to complete the task. Lower completion time indicates better performance.
Change in Montreal Cognitive Assessment Score
The Montreal Cognitive Assessment (MoCA) is a brief screening tool used to assess global cognitive function across multiple domains, including memory, attention, language, and executive function. It consists of a series of tasks, with scores ranging from 0 to 30, where higher scores indicate better cognitive function.
Change in the Digit Symbol Substitution Test Score
Participants are given a key pairing numbers with symbols and are asked to match as many symbols to the corresponding numbers as possible within a fixed time period. This test assesses processing speed. Performance is measured as the number of correct responses completed within the time limit, reported as a count (number of correct responses), with higher scores indicating greater performance.
Change in Handgrip Maximal Voluntary Contraction
Maximal voluntary contraction (MVC) will be assessed using a handgrip dynamometer to determine participants' maximal grip strength. MVC for each hand will be determined as the highest force, in kilograms (kg), produced across three trials. MVC will be measured at baseline and post-intervention (4 weeks) to explore changes over time. Prior to each intervention session, participants will complete one MVC trial per hand to calibrate exercise intensity at 30% MVC; these session-level MVC values will be used for exercise prescription only. Higher values indicate greater grip strength.
Change in Resting Heart Rate
Resting heart rate will be measured using an automated device on the right arm following a 5-minute seated rest period. After the initial measurement, a second and third measurement will be taken, each separated by a 1-minute rest interval. Heart rate will be recorded in beats per minute (bpm), with lower values generally indicating better cardiovascular function.
Expectancy of Cognitive Outcome
Participant expectancy of cognitive improvement will be assessed at baseline using a single-item 6-item Likert-type scale adapted from prior research, with the response options ranging from "a little improvement" to "extreme improvement." Higher scores indicate greater expectancy of improvement. This measure will be used to explore associations between expectancy and changes in cognitive function.
Post-Exercise Rating of Perceived Exertion (RPE)
Perceived exertion will be assessed immediately following each isometric handgrip contraction during each exercise session using the Borg 6-20 Rating of Perceived Exertion Scale. The scale ranges from 6 to 20, with higher scores indicating greater perceived exertion.
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