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NCT Number: NCT03981640

Neural Control of Kidney Blood Flow During Exercise in African American Adults

The goal of this clinical trials is to learn if healthy young African American (AA) adults have a larger change in their kidney blood flow during exercise compared to White (W) adults. The main questions that this study aims to answer are:

* Do healthy young AA adults have a larger decrease in kidney blood flow during exercise compared to W adults? * Do healthy young AA adults have a larger decrease in kidney blood flow during other types of stress compared to W adults?

During two visits in the research lab, participants will:

* Perform a fitness test * Perform cycling exercise while lying down * Undergo a cold hand test * Perform a mental math test

Completing this clinical trial will help researchers to understand more about why many AA adults have heart and kidney problems, so future research can study ways to reduce the number of AA adults who have these health issues.

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Key information

Conditions

Healthy Behavior Behavioral Symptoms Motor Activity Stress, Psychological

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Massachusetts Boston

Boston, Massachusetts, 02125, United States

Location status: Recruiting

Location contact

Rachel C Drew, PhD

CONTACT

[email protected]

617-287-4061

Rachel C Drew, PhD

PRINCIPAL_INVESTIGATOR

About this study

African American (AA) adults have a greater prevalence of developing cardiovascular and renal disease (CVRD) than White (W) adults. Elevated sympathetic nervous system activity is associated with increased incidence of CVRD. Physical exertion, such as exercise, acutely increases sympathetic nervous system activity directed towards the kidneys, resulting in renal vasoconstriction and reduced renal blood flow (RBF). Limited research shows that healthy young AA adults exhibit exaggerated sympathetic responsiveness both at rest and during sympathetic activation, which may be a major contributor to the increased risk of CVRD in this population. However, the acute renal vasoconstrictor response to any sympathetic nervous system activation has not been investigated to date in AA adults. During sympathetic nervous system activation such as exercise, sympathetic outflow to the kidneys in AA adults might be exaggerated, contributing to greater renal vasoconstriction and a larger reduction in RBF. Over time, this exaggerated neurovascular response to sympathetic activation could have a negative cumulative effect on the kidneys, which could be a contributing factor to the greater incidence of CVRD in this population.

Therefore, this study aims to examine the renal vasoconstrictor response to sympathetic stressors in healthy AA adults prior to development of CVRD, which will be achieved via two Specific Aims. In Specific Aim 1, the investigators will test the hypothesis that the renal vasoconstrictor response to acute dynamic exercise is exaggerated in healthy young AA compared to W adults. Specifically, the investigators will measure RBF and blood pressure at rest and during cycling exercise to calculate renal vascular resistance responses to exercise, enabling us to test the hypothesis that healthy young AA adults exhibit an exaggerated renal vasoconstrictor response to acute cycling exercise compared to healthy young W adults. In Specific Aim 2, the investigators will test the hypothesis that the renal vasoconstrictor response to non-exercise sympathetic stressors is exaggerated in healthy young AA compared to W adults. Specifically, the investigators will measure RBF and blood pressure at rest and during a cold pressor and mental stress tests to calculate renal vascular resistance responses to these non-exercise sympathetic stressors, enabling us to test the hypothesis that healthy young AA adults exhibit exaggerated renal vasoconstrictor responses to non-exercise sympathetic stressors compared to healthy young W adults.

Using the highly innovative approach of Doppler ultrasound to measure RBF during exercise and non-exercise sympathetic stressors non-invasively and with high temporal resolution will enable us to assess the renal vasoconstrictor response to sympathetic stressors in healthy AA adults prior to development of CVRD, so the underlying integrative physiological responses to sympathetic activation in AA adults can be understood. Findings from this study in this understudied yet clinically significant area will contribute to the ultimate goal of creating and implementing treatment strategies to reduce the risk of developing CVRD in AA adults.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Self-report as either African American or White racial identity
  • Born in United States
  • Both biological parents identify as same racial identity as participant
  • Recreationally active (participating in physical activity for at least 20 minutes per day, at least three times per week, but not training for competitive events)
  • Fluent in English

Exclusion criteria

  • Hispanic or Latino
  • Females who are pregnant or lactating
  • Cardiovascular or renal disease
  • Hypertension (blood pressure of more than or equal to 130/80 mmHg)
  • Diabetes
  • Obesity (body mass index of more than or equal to 30 kg/m2)
  • Smoker/Tobacco user
  • Acute medical conditions
  • Taking prescribed cardiovascular, antihypertensive, or renal medications

Treatment and study plan

Acute exercise

Other

Participants will lie in a semi-supine position with their feet attached to the pedals of a custom-arranged cycle ergometer. Participants' 40% heart rate reserve will be calculated, giving the target value to achieve during exercise based on appropriate resistance applied on the cycle ergometer, corresponding to a moderate exercise intensity. After a 5-minute resting baseline, participants will perform dynamic cycling exercise at steady state for up to 20 minutes. They will then stop exercising, and there will be a 5-minute recovery period. Beat-to-beat renal blood flow velocity (Doppler ultrasound), mean arterial blood pressure (finger photoplethysmographic cuff), and heart rate (electrocardiogram) will be recorded throughout. A rating of perceived exertion will be taken from participants during the last 30 seconds of steady-state cycling exercise.

Cold pressor test

Other

Participants will lie in a semi-supine position, and after a 3-minute resting baseline, participants will have their hand immersed in ice water for 2 minutes. This cold pressor test represents the non-exercise, physical sympathetic stressor. Participants' hand will then be removed from the ice water, followed by a 3-minute recovery period. Beat-to-beat renal blood flow velocity (Doppler ultrasound), mean arterial blood pressure (finger photoplethysmographic cuff), and heart rate (electrocardiogram) will be recorded throughout. Ratings of hand pain and cold perception will be taken from participants during the last 30 seconds of the cold pressor test.

Mental stress test

Other

Participants will lie in a semi-supine position, and after a 3-minute resting baseline, participants will perform a mental arithmetic task for 5 minutes. This mental stress test represents the non-exercise, psychological sympathetic stressor. Participants will be instructed to subtract a given number from a randomly selected three-digit number and verbally state their answer and continue to do so for the duration of the test. Participants will be instructed to state their answers as quickly and accurately as possible. Participants will then stop the arithmetic task, and a 3-minute recovery period will follow. Beat-to-beat renal blood flow velocity (Doppler ultrasound), mean arterial blood pressure (finger photoplethysmographic cuff), and heart rate (electrocardiogram) will be recorded throughout. A rating of perceived stress will be taken from participants during the last 30 seconds of the mental stress test.

Primary outcomes

  1. Change in renal vascular resistance during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the percent change from pre-acute exercise to during steady-state exercise will be assessed.

  2. Change in renal vascular resistance during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the percent change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  3. Change in renal vascular resistance during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the percent change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

Secondary outcomes

  1. Change in renal blood flow velocity during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  2. Change in mean arterial blood pressure during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  3. Change in systolic blood pressure during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  4. Change in diastolic blood pressure during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  5. Change in heart rate during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  6. Change in cardiac output during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  7. Change in stroke volume during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  8. Change in total peripheral resistance during acute exercise

    Time frame: Pre-acute exercise and during steady-state exercise

    For the acute exercise intervention, the absolute change from pre-acute exercise to during steady-state exercise will be assessed.

  9. Change in renal blood flow velocity during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  10. Change in mean arterial blood pressure during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  11. Change in systolic blood pressure during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  12. Change in diastolic blood pressure during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  13. Change in heart rate during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  14. Change in cardiac output during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  15. Change in stroke volume during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  16. Change in total peripheral resistance during cold pressor test

    Time frame: Pre-cold pressor test to after 30, 60, 90, and 120 seconds of cold pressor test

    For the cold pressor test intervention, the absolute change from pre-cold pressor test to 30-second intervals during the cold pressor test will be assessed.

  17. Change in renal blood flow velocity during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

  18. Change in mean arterial blood pressure during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

  19. Change in systolic blood pressure during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

  20. Change in diastolic blood pressure during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

  21. Change in heart rate during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

  22. Change in cardiac output during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

  23. Change in stroke volume during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

  24. Change in total peripheral resistance during mental stress test

    Time frame: Pre-mental stress test to after 1, 2, 3, 4, and 5 minutes of mental stress test

    For the mental stress test intervention, the absolute change from pre-mental stress test to 1-minute intervals during the mental stress test will be assessed.

Other outcomes

  1. Rating of perceived exertion during acute exercise

    Time frame: During last 30 seconds of steady-state exercise

    For the acute exercise intervention, the rating will be taken during the last 30 seconds of steady-state exercise. The Borg Scale of Perceived Exertion will be used, with which a rating from 6 to 20 will be taken, with 6 representing no exertion and 20 representing maximal exertion.

  2. Rating of hand pain during cold pressor test

    Time frame: During last 30 seconds of cold pressor test

    For the cold pressor test intervention, the rating will be taken during the last 30 seconds of the cold pressor test. A scale from 0 to 10 will be used to take the rating, with 0 representing no pain and 10 representing the worst possible pain.

  3. Rating of cold perception during cold pressor test

    Time frame: During last 30 seconds of cold pressor test

    For the cold pressor test intervention, the rating will be taken during the last 30 seconds of the cold pressor test. A scale from 0 to -11 will be used to take the rating, with 0 representing no perceived cold and -11 representing unbearable cold.

  4. Rating of perceived stress during mental stress test

    Time frame: During last 30 seconds of mental stress test

    For the mental stress test intervention, the rating will be taken during the last 30 seconds of the mental stress test. A scale from 0 to 4 will be used to take the rating, with 0 representing no perceived stress and 4 representing extremely stressful.

Study contacts

Contact information is provided by the study sponsor or research team.

Rachel C Drew, PhD

CONTACT

[email protected]

617-287-4061

Sponsors and collaborators

Lead sponsor

University of Massachusetts, Boston

Other

Collaborators

  • National Heart, Lung, and Blood Institute (NHLBI)

Registry information

Official study title

Neurovascular Control of Renal Blood Flow During Exercise in African American Adults

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
Jun 11, 2019
Registry last updated
Jun 26, 2026

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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