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NCT Number: NCT04887610

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.

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Key information

Conditions

Ischemic Preconditioning Dietary Exposure

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Guelph - Human Cardiovascular Physiology Laboratory

Guelph, Ontario, N1G 2W1, Canada

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Ischemic preconditioning

Procedure

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)

Ischemic preconditioning control

Procedure

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)

low fat meal

Dietary Supplement

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

High fat meal

Dietary Supplement

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.

Primary outcomes

  1. Forearm blood flow

    Time frame: Baseline - Immediately before active and control interventions

    Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  2. Forearm blood flow

    Time frame: Immediately after active and control interventions (IPC only)

    Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  3. Forearm blood flow

    Time frame: 1 hour after active and control interventions (Diet intervention only)

    Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  4. Forearm blood flow

    Time frame: 2 hours after active and control interventions (Diet intervention only)

    Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  5. Forearm blood flow

    Time frame: 3 hours after active and control interventions (Diet intervention only)

    Doppler ultrasound - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  6. Forearm vascular conductance

    Time frame: Baseline - Immediately before active and control interventions

    Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  7. Forearm vascular conductance

    Time frame: Immediately after active and control interventions (IPC only)

    Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  8. Forearm vascular conductance

    Time frame: 1 hour after active and control interventions (Diet intervention only)

    Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  9. Forearm vascular conductance

    Time frame: 2 hours after active and control interventions (Diet intervention only)

    Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  10. Forearm vascular conductance

    Time frame: 3 hours after active and control interventions (Diet intervention only)

    Blood flow divided by blood pressure - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

Secondary outcomes

  1. Blood pressure

    Time frame: Baseline - Immediately before active and control interventions

    Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  2. Blood pressure

    Time frame: Immediately after active and control interventions (IPC only)

    Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  3. Blood pressure

    Time frame: 1 hour after active and control interventions (Diet intervention only)

    Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  4. Blood pressure

    Time frame: 2 hours after active and control interventions (Diet intervention only)

    Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  5. Blood pressure

    Time frame: 3 hours after active and control interventions (Diet intervention only)

    Finger plethysmography - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  6. Heart rate

    Time frame: Baseline - Immediately before active and control interventions

    ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  7. Heart rate

    Time frame: Immediately after active and control interventions (IPC only)

    ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  8. Heart rate

    Time frame: 1 hour after active and control interventions (Diet intervention only)

    ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  9. Heart rate

    Time frame: 2 hours after active and control interventions (Diet intervention only)

    ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

  10. Heart rate

    Time frame: 3 hours after active and control interventions (Diet intervention only)

    ECG - tested at rest and during rhythmic handgrip exercise with and without lower body negative pressure

Sponsors and collaborators

Lead sponsor

University of Guelph

Other

Registry information

Important dates

Study start
2021
Primary completion
2022
Study completion
2022
First posted
May 14, 2021
Registry last updated
Mar 30, 2023

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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