Factors That Influence Blood Vessel Regulation During Exercise in Humans

This study will examine two separate interventions: 1) the effects of ischemic preconditioning or 2) a high fat meal on the capacity of the brachial artery to overcome sympathetic activation and dilate during exercise (also known as functional sympatholysis). Participants will be asked to complete rhythmic handgrip exercise with and without the application of -20 mmHg lower body negative pressure to increase sympathetic activation. Doppler ultrasound will be used to continuously measure brachial artery blood flow. Participants will complete the handgrip exercise and lower body negative pressure before and after the applications of each interventions. Participants may elect to only complete one intervention rather than complete both protocols. Intervention one is active or control ischemic preconditioning. Intervention two is high or low fat meals.

Study Overview

• Status: Completed
• Conditions: Dietary Exposure; Ischemic Preconditioning
• Intervention / Treatment: Procedure: Ischemic preconditioning control; Procedure: Ischemic preconditioning; Dietary supplement: Low fat meal; Dietary supplement: High fat meal

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Guelph, Ontario, Canada, N1G 2W1
      • University of Guelph - Human Cardiovascular Physiology Laboratory

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 50 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 18 years or older
• Healthy

Exclusion Criteria:

• History of smoking (tobacco or cannabis), defined as any smoking within the past 3 months
• Diagnosed cardiovascular or metabolic disease(s)
• Recent musculoskeletal injury handgrip exercise
• Prescription of chronic medications other than oral contraceptives
• History of hypertension or presence of arrhythmia

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: High fat meal	Dietary supplement: Low fat meal; Meal containing 1006 calories, 1 g fat, 0.2 g saturated fat, 0 g trans fat, 20 mg cholesterol, 191 g carbohydrates, 60 g protein, 1560 mg sodium
Sham Comparator: Ischemic preconditioning control	Procedure: Ischemic preconditioning control; Four 5-minute cycles of 20 mmHg cuff inflation of the brachial artery, each separated by 5-minutes deflated recovery (i.e. 40 minutes total time)
Active Comparator: Ischemic preconditioning	Procedure: Ischemic preconditioning; Four 5-minute cycles of 200 mmHg cuff inflation of the brachial artery, each separated by 5-minutes deflated recovery (i.e. 40 minutes total time)
Placebo Comparator: Low fat meal	Dietary supplement: High fat meal; Meal containing 1030 calories, 62 g fat, 23 g saturated fat, 0.5 g trans fat, 445 mg cholesterol, 76 g carbohydrates, 41 g protein, 2080 mg sodium.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Forearm blood flow	Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Baseline - Immediately before active and control interventions
Forearm vascular conductance	Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Baseline - Immediately before active and control interventions
Forearm blood flow	Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Immediately after active and control interventions (IPC only)
Forearm blood flow	Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	1 hour after active and control interventions (Diet intervention only)
Forearm blood flow	Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	2 hours after active and control interventions (Diet intervention only)
Forearm blood flow	Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	3 hours after active and control interventions (Diet intervention only)
Forearm vascular conductance	Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Immediately after active and control interventions (IPC only)
Forearm vascular conductance	Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	1 hour after active and control interventions (Diet intervention only)
Forearm vascular conductance	Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	2 hours after active and control interventions (Diet intervention only)
Forearm vascular conductance	Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	3 hours after active and control interventions (Diet intervention only)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure	Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Baseline - Immediately before active and control interventions
Heart rate	ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Baseline - Immediately before active and control interventions
Blood pressure	Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Immediately after active and control interventions (IPC only)
Blood pressure	Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	1 hour after active and control interventions (Diet intervention only)
Blood pressure	Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	2 hours after active and control interventions (Diet intervention only)
Blood pressure	Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	3 hours after active and control interventions (Diet intervention only)
Heart rate	ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	Immediately after active and control interventions (IPC only)
Heart rate	ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	1 hour after active and control interventions (Diet intervention only)
Heart rate	ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	2 hours after active and control interventions (Diet intervention only)
Heart rate	ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure	3 hours after active and control interventions (Diet intervention only)

Collaborators and Investigators

• Sponsor: University of Guelph

Study record dates

Study Major Dates

• Study Start (Actual): May 20, 2021
• Primary Completion (Actual): November 15, 2022
• Study Completion (Actual): November 15, 2022

Study Registration Dates

• First Submitted: April 1, 2021
• First Submitted That Met QC Criteria: May 10, 2021
• First Posted (Actual): May 14, 2021

Study Record Updates

• Last Update Posted (Actual): March 30, 2023
• Last Update Submitted That Met QC Criteria: March 27, 2023
• Last Verified: March 1, 2023

More Information

Terms related to this study

• Other Study ID Numbers: 20-11-008

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

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