Cardiovascular Reactivity to Physical Stress (REACT)

Cardiovascular Reactivity to Physical Stress: Strategies and Mechanisms

It is well-accepted that an exaggerated blood pressure (BP) response to physical stress has a prognostic value, indicating a higher cardiovascular risk (e.g., sudden cardiac death, myocardial infarction, future hypertension, and left ventricular hypertrophy). However, there is a limited understanding of the underlying mechanisms and therapuetic strategies modulating this response. Therefore, this pilot project aims to explore whether one session of low-volume high-intensity interval training (low-volume HIIT) or combined intermittent heat and cold bath (sauna+cold bath) can decrease BP responses to physical stress. Furthermore, the secondary goal is to investigate whether one brief session learning about positive stress expectations magnifies the decrease in BP following low-volume HIIT and sauna+ cold bath.

Study Overview

• Status: Recruiting
• Conditions: Stress, Physiological; Blood Pressure
• Intervention / Treatment: Other: Low-volume high intensity exercise; Other: Combined intermittent sauna and cold water bath (sauna+cold bath).

• Study Type: Interventional
• Enrollment (Estimated): 58
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Ann-Katrin Grotle, PhD; Phone Number: +4790960580; Email: ann-katrin.grotle@hvl.no
• Study Contact Backup: Name: Hege R Eriksen, PhD; Email: hege.randi.eriksen@hvl.no

Study Locations

• Norway
  • Vestland
    • Bergen, Vestland, Norway, 5063
      • Recruiting
      • Western Norway University of Applied Sciences
      • Contact: Ann-Katrin Grotle; Phone Number: +4790960580; Email: ann-katrin.grotle@hvl.no

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Male or female between 18 to 50 years
• Non-smoker.
• Non-obese (<30 kg/m2).
• Able to walk on a treadmill and cycle on a stationary bike without problems.
• No or little (frequency < 2 times per month) experience swimming with sauna and cold water.
• Proficient in Norwegian and able to provide informed consent.

Exclusion Criteria:

• Current or previous regular smoker
• Addictions to alcohol or illegal drugs
• Diagnosed with cardiovascular, respiratory, metabolic, or autoimmune diseases
• Taking prescription medication with known cardiovascular effects
• Judgment by a medical provider that exercise, heat therapy, or hydrotherapy poses an undue burden or risk.
• Cognitive or psychiatric impairment
• Lack of proficiency in Norwegian language oral or writing skills that will hamper the ability to participate in the interventions and fill out questionnaires.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Positive stress education (PSE); This intervention will consist of standardized information about the relationships between expectations and the stress response. Using the CATS as a theoretical framework, the participants will be explained that when people face stressors, i.e., pain, heat, and cold water, the expectations about handling the situation will influence both the experience (e.g., pain) and the physiological stress response.	Other: Low-volume high intensity exercise; This intervention will consist of 10 x 10-second interval sprints on a stationary bicycle interspersed with 50-second breaks between repetitions. The cycle resistance will be adjusted to the level equaling the highest power output, which will be determined during warm-up sprints.; Other: Combined intermittent sauna and cold water bath (sauna+cold bath).; This intervention will consist of 3x10 min bouts in the dry sauna interspersed with 2x 60 seconds of cold water immersion up to the neck.
Sham Comparator: Neutral control; To control for the PSE intervention, the participants will receive 15 min of neutral information about the effects of physical exercise on cardiovascular fitness.	Other: Low-volume high intensity exercise; This intervention will consist of 10 x 10-second interval sprints on a stationary bicycle interspersed with 50-second breaks between repetitions. The cycle resistance will be adjusted to the level equaling the highest power output, which will be determined during warm-up sprints.; Other: Combined intermittent sauna and cold water bath (sauna+cold bath).; This intervention will consist of 3x10 min bouts in the dry sauna interspersed with 2x 60 seconds of cold water immersion up to the neck.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure (unit: mmHg) response to laboratory stressors	Response will be calculated as the change from baseline to peak. Stressors employed include handgrip exercise, post-exercise ischemia, and cold pressor test.	Assessment will be completed before intervention and approximately 30 minutes after intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Resting blood pressure (mmHg).		Assessment will be completed before intervention and approximately 30 minutes after intervention
Endothelial function (% dilation)	Endothelial function will be assessed using the flow-mediated dilation technique following current guidelines.	Assessment will be completed before intervention and approximately 30 minutes after intervention.
Subjective ratings of expectancies (point score).	Stress, pain, heat, and cold response expectancies will be assessed with single questions specifically targeted to the interventions and experimental tests using a Numeric Rating Scale (NRS) ranging from 0 = no stress, no pain, no discomfort (heat, cold) at all to 10 = worst possible pain, stress, heat/cold discomfort.	Assessment will be completed before intervention and approximately 30 minutes after intervention.

Collaborators and Investigators

• Sponsor: Western Norway University of Applied Sciences

Study record dates

Study Major Dates

• Study Start (Actual): February 19, 2024
• Primary Completion (Estimated): January 1, 2027
• Study Completion (Estimated): January 1, 2027

Study Registration Dates

• First Submitted: February 11, 2024
• First Submitted That Met QC Criteria: March 11, 2024
• First Posted (Actual): March 19, 2024

Study Record Updates

• Last Update Posted (Actual): March 19, 2024
• Last Update Submitted That Met QC Criteria: March 11, 2024
• Last Verified: March 1, 2024

More Information

Terms related to this study

• Keywords: Metaboreflex; Cardiovascular reactivity; Neural control of blood pressure; Cold pressor response
• Other Study ID Numbers: 2688791

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No