Exercise-Induced Kidney Blood Flow Response in African American Adults

Overseen By Rachel C Drew, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: University of Massachusetts, Boston

Must not be taking: Cardiovascular, Antihypertensive, Renal

Disqualifiers: Hypertension, Diabetes, Obesity, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

32 Participants Needed

Trial Summary

What is the purpose of this trial?

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). 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 to test the hypotheses that the renal vasoconstrictor response to acute dynamic exercise, as well as a cold pressor and mental stress tests, is exaggerated in healthy young AA compared to W adults. To test these hypotheses, the investigators will measure RBF and blood pressure at rest and during cycling exercise and a cold pressor and mental stress tests to calculate renal vascular resistance responses to these acute interventions. 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.

Do I need to stop my current medications for the trial?

Yes, you will need to stop taking any prescribed cardiovascular, antihypertensive, or renal medications to participate in this trial.

What data supports the effectiveness of the treatment involving exercise and cold pressor tests in African American adults?

Research shows that regular aerobic exercise can reduce the exaggerated blood pressure response to cold stress in African Americans, which may help prevent high blood pressure. Studies found that physically active individuals had better cardiovascular responses during cold stress tests compared to inactive ones. ^{1 2 3 4 5}

Is exercise-induced kidney blood flow response safe for African American adults?

The studies suggest that physical activities like aerobic exercise and cold pressor tests are generally safe for African American adults, as they have been used to study blood pressure responses without reported safety issues. However, these activities can cause temporary changes in blood pressure and heart rate, which are normal responses to stress and exercise. ^{2 3 5 6 7}

How does the treatment of exercise-induced kidney blood flow response differ from other treatments?

This treatment is unique because it combines physical activity, cold exposure, and mental stress to study their effects on kidney blood flow, particularly in African American adults. Unlike standard drug treatments, this approach uses natural stimuli to understand physiological responses, which may provide insights into managing conditions like hypertension (high blood pressure) without medication. ^{2 3 8 9 10}

Research Team

Rachel C Drew, PhD

Principal Investigator

University of Massachusetts, Boston

Eligibility Criteria

This trial is for African American and White adults born in the U.S., fluent in English, who are active but not training competitively. Participants must have parents of the same racial identity. It excludes pregnant or lactating women, those with hypertension, diabetes, obesity, smokers, or anyone with cardiovascular/renal disease.

Inclusion Criteria

You exercise regularly for at least 20 minutes per day, three times per week, but you are not a competitive athlete.

Born in United States

Fluent in English

Exclusion Criteria

I have heart or kidney disease.

You use tobacco or smoke cigarettes.

I am not pregnant or breastfeeding.

Timeline

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Exercise Intervention

Participants undergo acute dynamic exercise to measure renal blood flow and blood pressure responses

1 session

1 visit (in-person)

Cold Pressor and Mental Stress Tests

Participants undergo cold pressor and mental stress tests to measure renal vascular resistance and other cardiovascular responses

1 session

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after interventions

4 weeks

Treatment Details

Interventions

• Acute exercise
• Cold pressor test
• Mental stress test

Trial Overview The study investigates how acute exercise and stress tests (cold pressor test and mental stress test) affect kidney blood flow in healthy African American adults compared to Whites. The goal is to understand if there's an exaggerated response that could contribute to higher rates of cardiovascular and renal diseases.

Participant Groups

Group I: White Adults Experimental Treatment 3 Interventions

White adults will undergo the interventions of acute exercise, a cold pressor test, and a mental stress test while beat-to-beat renal blood flow velocity, mean arterial blood pressure, and heart rate are recorded.

Group II: African American Adults Experimental Treatment 3 Interventions

African American adults will undergo the interventions of acute exercise, a cold pressor test, and a mental stress test while beat-to-beat renal blood flow velocity, mean arterial blood pressure, and heart rate are recorded.

Who Is Running the Clinical Trial?

University of Massachusetts, Boston

Lead Sponsor

Trials

42

Recruited

17,800+

National Heart, Lung, and Blood Institute (NHLBI)

Collaborator

Trials

3,987

Recruited

47,860,000+

Findings from Research

In a study involving 20 young women (12 White and 8 Black), it was found that Black women had significantly higher brachial mean arterial and diastolic blood pressure compared to White women after acute supramaximal exercise, indicating potential differences in cardiovascular responses.

Additionally, Black women exhibited lower heart rate variability, suggesting a different autonomic modulation compared to White women, which may influence how exercise prescriptions should be tailored for different racial groups.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Racial Differences in Blood Pressure and Autonomic Recovery Following Acute Supramaximal Exercise in Women. Bajdek, N., Merchant, N., Camhi, SM., et al.[2023]

In a study of 30 young adult African-American males, those who were physically active had significantly higher peak oxygen consumption compared to their inactive counterparts, indicating better cardiovascular fitness.

Despite the differences in fitness levels, both physically active and inactive groups showed similar blood pressure responses during a cold pressor test, suggesting that regular physical activity does not necessarily lead to a reduced blood pressure reaction to acute stress in this population.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Physical activity and blood pressure responsiveness to the cold pressor test in normotensive young adult African-American males. Bond, V., Adams, RG., Vaccaro, P., et al.[2022]

Aerobic exercise significantly reduces blood pressure reactivity to stress in healthy African-American females, as shown by a 6.3% decrease in systolic pressure during a cold pressor test after a 6-week training program.

The study involved 13 participants (8 trained and 5 sedentary), and the trained group also showed a notable 24.1% increase in their peak oxygen uptake (VO2peak), indicating improved cardiovascular fitness, which may help lower hypertension risk.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Aerobic exercise attenuates blood pressure reactivity to cold pressor test in normotensive, young adult African-American women. Bond, V., Mills, RM., Caprarola, M., et al.[2022]

In a study involving 13 non-hypertensive volunteers, cardiovascular responses to the cold pressor test (CPT) were found to be reproducible, indicating reliable measurements of heart rate, blood pressure, blood flow, and skin temperature.

Exercise significantly reduced the cardiovascular responses to cold stress, suggesting that regular physical activity may help mitigate the body's reaction to cold, which could be beneficial in identifying individuals at risk for hypertension and promoting preventative exercise programs.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Reproducibility of exercise-induced modulation of cardiovascular responses to cold stress. Rashed, HM., Leventhal, G., Madu, EC., et al.[2019]

In a study of 83 normotensive Black and White men and women aged 25 to 44, Black participants exhibited significantly higher diastolic blood pressure responses during a cold pressor test compared to White participants, indicating potential racial differences in cardiovascular reactivity.

The study also found that exercise led to greater systolic blood pressure increases in Black women compared to Black men and White women, suggesting that both race and sex influence physiological responses to stressors.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Cardiovascular and neurohumoral responses to behavioral challenge as a function of race and sex. Tischenkel, NJ., Saab, PG., Schneiderman, N., et al.[2022]

In a study of 119 normotensive and mildly to moderately hypertensive individuals, baseline blood pressure at rest was found to be a strong predictor of ambulatory blood pressure at work, indicating its importance in monitoring blood pressure levels.

Among various stress-inducing tasks, psychological challenges like structured interviews and video games were the most significant predictors of ambulatory blood pressure, with the cold pressor test showing a notably stronger correlation for diastolic blood pressure in black participants compared to white participants.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Predicting home and work blood pressure measurements from resting baselines and laboratory reactivity in black and white Americans. Ironson, GH., Gellman, MD., Spitzer, SB., et al.[2022]

In a study examining cardiovascular responses to stress in women, Black participants showed a slower recovery of diastolic blood pressure after mental arithmetic tasks, indicating potential differences in cardiovascular reactivity compared to White participants.

During the cold face stimulus, Black women exhibited significantly greater increases in systolic blood pressure than White women, suggesting that race may influence vascular responses to stress, although parental history of hypertension did not significantly affect these responses.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Race, parental history of hypertension, and patterns of cardiovascular reactivity in women. Anderson, NB., Lane, JD., Taguchi, F., et al.[2022]

In a study involving 12 baboons, renal blood flow decreased by about 19% during dynamic leg exercise, indicating that exercise can significantly affect kidney blood supply.

The decrease in renal blood flow occurred quickly within 1.5 minutes of exercise onset and was primarily controlled by neural mechanisms, similar to responses observed in humans.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Decreased renal blood flow in the baboon during mild dynamic leg exercise. Hohimer, AR., Smith, OA.[2017]

In two studies involving 10 healthy young adults, neither 30 minutes of moderate intensity aerobic exercise nor 30 seconds of maximal effort anaerobic exercise changed the increase in renal vascular resistance (RVR) during sympathetic stimulation, indicating that prior exercise does not affect kidney response to stress.

Both types of exercise did not alter the renal blood velocity response to sympathetic stimulation, suggesting that the body's ability to regulate kidney blood flow remains consistent regardless of prior aerobic or anaerobic activity.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Renal Hemodynamics During Sympathetic Activation Following Aerobic and Anaerobic Exercise. Schlader, ZJ., Chapman, CL., Benati, JM., et al.[2020]

In healthy humans, static handgrip exercise leads to a significant decrease in renal cortical blood flow and an increase in renal vascular resistance, indicating that exercise affects kidney blood supply.

The study identified that both central command and mechanoreflex mechanisms contribute to the early decrease in renal blood flow during exercise, while the muscle metaboreflex further decreases blood flow after exercise, suggesting complex regulatory mechanisms at play.

NCBI (Pubmed)

pubmed.ncbi.nlm.nih.gov

Modulation of renal cortical blood flow during static exercise in humans. Middlekauff, HR., Nitzsche, EU., Nguyen, AH., et al.[2019]

References

1. Switzerland pubmed.ncbi.nlm.nih.gov

Racial Differences in Blood Pressure and Autonomic Recovery Following Acute Supramaximal Exercise in Women. [2023]

2. United States pubmed.ncbi.nlm.nih.gov

Physical activity and blood pressure responsiveness to the cold pressor test in normotensive young adult African-American males. [2022]

3. United States pubmed.ncbi.nlm.nih.gov

Aerobic exercise attenuates blood pressure reactivity to cold pressor test in normotensive, young adult African-American women. [2022]

4. Germany pubmed.ncbi.nlm.nih.gov

Reproducibility of exercise-induced modulation of cardiovascular responses to cold stress. [2019]

5. United States pubmed.ncbi.nlm.nih.gov

Cardiovascular and neurohumoral responses to behavioral challenge as a function of race and sex. [2022]

6. United States pubmed.ncbi.nlm.nih.gov

Predicting home and work blood pressure measurements from resting baselines and laboratory reactivity in black and white Americans. [2022]

7. United States pubmed.ncbi.nlm.nih.gov

Race, parental history of hypertension, and patterns of cardiovascular reactivity in women. [2022]

8. United States pubmed.ncbi.nlm.nih.gov

Decreased renal blood flow in the baboon during mild dynamic leg exercise. [2017]

9. Switzerland pubmed.ncbi.nlm.nih.gov

Renal Hemodynamics During Sympathetic Activation Following Aerobic and Anaerobic Exercise. [2020]

10. United States pubmed.ncbi.nlm.nih.gov

Modulation of renal cortical blood flow during static exercise in humans. [2019]