# Evaluation of Racial Differences in Cardiorespiratory Fitness Decline with Aging & Underlying Biological Mechanisms

> **NIH NIH R03** · UT SOUTHWESTERN MEDICAL CENTER · 2021 · $163,875

## Abstract

Project Abstract:
Heart failure (HF) with preserved ejection fraction (HFpEF) is common in older adults and increasing in
prevalence. Furthermore, there are substantial racial disparities in the burden of HF, including HFpEF, such
that African American (AA) have much higher prevalence of HF than other races. In a series of epidemiological
studies, we have demonstrated that low cardiorespiratory fitness (CRF), measured as peak oxygen uptake
(peak VO2) on a maximal stress test, is a strong independent predictor of higher risk of HF, particularly
HFpEF, in older adults. Furthermore, CRF levels among AA are consistently lower as compared with other
races. Taken together, low CRF and accelerated age-related decline in CRF may be key contributors to the
racial differences in the burden of HF. A better understanding of the mechanisms underlying the racial
disparities in prevalence of low CRF and age-related CRF decline is key to developing novel, effective
approaches to prevention of HF in older AA adults. Accordingly, in this study, we aim to evaluate the racial
differences in age-related decline in CRF and their underlying biological mechanisms. To this end, we will
perform a nested case-control study within the Dallas Heart Study (DHS), a multi-ethnic cohort of community-
dwelling individuals, including older AA and white adults matched for age, sex, and risk factors (BMI, systolic
blood pressure, diabetes status) who underwent CRF testing in middle-age (mean age 50-55) as part of the
DHS phase 2 visit (2007-09) and are participating in the DHS phase 3 10-years later (2019-2022). Participants
will undergo repeat CRF assessment and comprehensive state-of-the-art phenotyping to comprehensively
evaluate the potential mechanisms of racial differences in CRF, including the following: stroke volume reserve
by echocardiogram, heart rate reserve, myocardial perfusion, myocardial energetics by cardiac MRI, skeletal
muscle energetics assessment by 7T MRI, and regional adipose tissue by whole body MRI. Peak VO2
combined with its central and peripheral determinants will be compared among matched AA and white
participants in the DHS phase 3. Successful completion of these two aims will quantify the CRF decline in AA
versus white older individuals for the first time and elucidate specific mechanisms, thereby, providing critical
insight into the underlying pathophysiologic mechanisms of low CRF.

## Key facts

- **NIH application ID:** 10260503
- **Project number:** 5R03AG067960-02
- **Recipient organization:** UT SOUTHWESTERN MEDICAL CENTER
- **Principal Investigator:** Ambarish Pandey
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $163,875
- **Award type:** 5
- **Project period:** 2020-09-15 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10260503

## Citation

> US National Institutes of Health, RePORTER application 10260503, Evaluation of Racial Differences in Cardiorespiratory Fitness Decline with Aging & Underlying Biological Mechanisms (5R03AG067960-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10260503. Licensed CC0.

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