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Trial registered on ANZCTR


Registration number
ACTRN12624000814572
Ethics application status
Approved
Date submitted
18/06/2024
Date registered
2/07/2024
Date last updated
2/07/2024
Date data sharing statement initially provided
2/07/2024
Type of registration
Prospectively registered

Titles & IDs
Public title
Hot-water immersion or exercise training for hauora in people with hypertension
Scientific title
Hot-water immersion or exercise training for health and well-being (hauora) in people with hypertension
Secondary ID [1] 312233 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Hypertension 333973 0
Condition category
Condition code
Cardiovascular 330641 330641 0 0
Hypertension

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Participants will be randomised to either 3 sessions per week of hot-water immersion in 40°C water or high-intensity interval training, for 8 weeks.

Hot water immersion (40°C)
Location: School of Physical Education, Sport and Exercise Sciences Aquatic Facility (University of Otago, Dunedin).
Supervision: This session will be supervised by an American College Sports Medicine (ACSM) registered clinical exercise physiologist (CEP) and a research assistant; all supervising researchers are first aid trained. Attendance and session particulars (e.g., physiological indices etc.) will be recorded at each session by the supervising researcher.
Exposure: Participants will complete three hot-water immersion sessions per week in 40°C water. Participants will be seated (or semi-recumbent) with water approximately top-sternal level.
Duration: Bathing duration will progressively increase from 20 to 30 min if tolerable (20 min first week, 25 min second week and 30 min third and subsequent weeks).
Intervention code [1] 328715 0
Treatment: Other
Comparator / control treatment
High-intensity interval training (HIIT)

Location: School of Physical Education Sport and Exercise Sciences Exercise Clinic (University of Otago, Dunedin).
Supervision: This session will be supervised by an American College Sports Medicine (ACSM) registered clinical exercise physiologist (CEP) and a research assistant; all supervising researchers are first aid trained. Attendance and session particulars (e.g., physiological indices etc.) will be recorded at each session by the supervising researcher.
Exposure: HIIT will be performed 3 times a week using a cross-trainer, arm ergometer or cycle (participant preference). Each session will begin with a 5-min warm-up on an exercise modality of the participants choosing. Initial sessions will begin with 6 x 60 s intervals, with recovery (90 s) in between intervals. Interval duration will remain constant throughout the intervention, with the aim of increasing the number of intervals to 8 and recovery duration decreasing to 60 s, Exercise intensity will initially be set at 85% of each participants VO2peak, before increasing each interval until a score of 7/10 on the rating of perceived exertion (RPE) scale is achieved; this corresponding workload will be used for subsequent intervals. As fitness increases, workload will increase to maintain this RPE,. Each session will last ~15 min and include a cool-down with light-intensity, whole-body flexibility exercise.
Duration: Participants will complete 8 weeks of HIIT.
Control group
Active

Outcomes
Primary outcome [1] 338389 0
Change in mean 24-hour resting blood pressure.
Timepoint [1] 338389 0
Baseline (pre-intervention) and 24-hours post-intervention. Ambulatory blood pressure will also be measured immediately after the first sessions in week one and four of the intervention.
Secondary outcome [1] 435905 0
Physical Function
Timepoint [1] 435905 0
Baseline (pre-intervention) and 24-hours post-intervention.
Secondary outcome [2] 435906 0
Resting blood pressure.
Timepoint [2] 435906 0
Baseline (pre-intervention), during and immediately post each session, and 24-hours post-intervention.
Secondary outcome [3] 435910 0
Heart rate
Timepoint [3] 435910 0
Baseline (pre-intervention), immediately before, during and after each session and 24-hours post-intervention.
Secondary outcome [4] 435915 0
Plasma Volume
Timepoint [4] 435915 0
Before and 24-hours after intervention sessions one and six only.
Secondary outcome [5] 435919 0
Quality of life
Timepoint [5] 435919 0
Baseline (pre-intervention) and 24-hours post-intervention.
Secondary outcome [6] 435920 0
7 day physical activity levels
Timepoint [6] 435920 0
Baseline (pre-intervention) and 24-hours post-intervention.
Secondary outcome [7] 435921 0
Anaerobic threshold
Timepoint [7] 435921 0
Baseline (pre-intervention) and 24-hours post-intervention.
Secondary outcome [8] 435925 0
Psychophysiological Status
Timepoint [8] 435925 0
Baseline (pre-intervention), during each session, and 24-hours post-intervention.
Secondary outcome [9] 436450 0
Ventricular ectopic burden
Timepoint [9] 436450 0
During session one and during the final session

Eligibility
Key inclusion criteria
- Aged 35 years or older;
- Prescribed and regularly taking at least one anti-hypertensive medication;
-Fulfils the Physical Activity Readiness Questionnaire Plus questionnaire criteria, or participant's physician provides medical clearance for study participation;
- Able to give written consent;
- Able to travel to the study centre to complete all sessions
Minimum age
35 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
-Aged less than 35 years;
-Contraindication to maximal exercise testing;
-Not "passing" the Physical Activity Readiness Questionnaire Plus questionnaire, and physician refuses medical clearance for study participation;
-Angina;
-Recent myocardial infarction (less than 3 months ago);
-Implanted cardiac device (i.e. ICD, pacemaker etc.);
-Heat intolerance;
-Current pregnancy;
-History of large blood pressure decreases or fainting;
-New anti-hypertensive pharmaceutical initiated recently (i.e., less than 30 days since initiation);
-Any other medical condition deemed a significant risk to study participation.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation will be concealed in an a sealed opaque envelope.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation).
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
8/07/2024
Actual
Date of last participant enrolment
Anticipated
7/03/2025
Actual
Date of last data collection
Anticipated
2/05/2025
Actual
Sample size
Target
40
Accrual to date
Final
Recruitment outside Australia
Country [1] 26362 0
New Zealand
State/province [1] 26362 0
Dunedin

Funding & Sponsors
Funding source category [1] 316610 0
University
Name [1] 316610 0
University of Otago
Country [1] 316610 0
New Zealand
Funding source category [2] 316757 0
Charities/Societies/Foundations
Name [2] 316757 0
Lottery Health Research
Country [2] 316757 0
New Zealand
Primary sponsor type
University
Name
University of Otago
Address
Country
New Zealand
Secondary sponsor category [1] 318863 0
None
Name [1] 318863 0
Address [1] 318863 0
Country [1] 318863 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 315396 0
University of Otago Human Ethics Committee (Health)
Ethics committee address [1] 315396 0
https://www.otago.ac.nz/council/committees/committees/humanethicscommittees
Ethics committee country [1] 315396 0
New Zealand
Date submitted for ethics approval [1] 315396 0
13/05/2024
Approval date [1] 315396 0
24/05/2024
Ethics approval number [1] 315396 0

Summary
Brief summary
The purpose of this study is to evaluate the effectiveness of an 8-week hot-water immersion or high-intensity interval training (exercise) intervention on ambulatory blood pressure. This study aims to compare hot-water immersion or high-intensity interval training for improving ambulatory blood pressure in people with hypertension. It is hypothesised that 8-weeks of regular hot-water immersion exposure will improve ambulatory blood pressure to a greater extent than exercise.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 134570 0
Dr Brendon Roxburgh
Address 134570 0
School of Physical Education, Sport ad Exercise Sciences, 55 Union Street, Dunedin 9012, New Zealand
Country 134570 0
New Zealand
Phone 134570 0
+64 274632376
Fax 134570 0
Email 134570 0
[email protected]
Contact person for public queries
Name 134571 0
Brendon Roxburgh
Address 134571 0
School of Physical Education, Sport ad Exercise Sciences, 55 Union Street, Dunedin 9012, New Zealand
Country 134571 0
New Zealand
Phone 134571 0
+64 274632376
Fax 134571 0
Email 134571 0
[email protected]
Contact person for scientific queries
Name 134572 0
Brendon Roxburgh
Address 134572 0
School of Physical Education, Sport ad Exercise Sciences, 55 Union Street, Dunedin 9012, New Zealand
Country 134572 0
New Zealand
Phone 134572 0
+64 274632376
Fax 134572 0
Email 134572 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.