None listed
Conditions
Brief summary
This 4x4 randomised crossover study will aim to recruit 10 participants taking at least one anti-hypertensive medication. Participants will complete 4 sessions: 1) 30-min whole-body (chest deep) hot-water immersion (40°C), 2) 30-min waist deep hot-water immersion (40°C), 3) 30-min lower-limb hot-water immersion (below knee depth deep in 40°C), and 4) 30-min control (no exposure). Physiological measures will be taken during each exposure to characterise the stimulus (e.g., beat-to-beat blood pressure, heart rate). Following each exposure participants will be fitted with an ambulatory blood pressure monitor (and accelerometer to confirm standardisation of activity levels) for the following 24 h to quantify the magnitude and duration of post-session hypotension.
Interventions
All participants will complete 3 water immersion sessions and a control session (in a randomised order): 1) 30-min whole-body hot-water immersion (40°C; chest depth), 2) 30-min waist deep hot-water immersion (40°C), 3) 30-min lower-limb hot-water immersion (~40°C; below knee depth). There will be a 4-day washout between exposures. 1. 30-min whole-body 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 of Sports Medicine (ACSM) registered clinical exercise physiologist (CEP), and the primary investigator (PI) or 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 a single 30-min hot water immersion session in 40 °C water. Participants will be seated upright with water approximately nipple level. Duration: 30 min. 2. 30-min waist-deep 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 of Sports Medicine (ACSM) registered clinical exercise physiologist (CEP), and the PI or 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 a single 30-min hot water immersion session in 40 °C water. Participants will be seated upright with water approximately waist deep level. Duration: 30 min. 3. 30-min lower-limb 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 of Sports Medicine (ACSM) registered clinical exercise physiologist (CEP), and the PI or 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 a single 30-min hot water immersion session in 40 °C water. Participants will be seated upright with water approximately at below knee level. Duration: 30 min.
Sponsors
University of Otago
Study design
Allocation
Randomised controlled trial
Primary purpose
Treatment
Eligibility
Sex/Gender
All
Age
35 Years to 85 Years
Healthy volunteers
No
Inclusion criteria
- Aged > 35 y or older; - Prescribed and regularly taking at least one anti-hypertensive medication; - Able to give written consent; - Able to travel to the study centre to complete all sessions.
Exclusion criteria
- Aged < 35 y; - Contraindication to maximal exercise testing; - Unstable angina; - Recent myocardial infarction (< 3 months ago); - History of orthostatic intolerance/hypotension; - Current pregnancy; - New anti-hypertensive pharmaceutical initiated recently (i.e., > 30 days since initiation); - Any other medical condition deemed a significant risk to study participation.
Outcome results
None listed