Ethnic-specific determinants of exercise capacity in a healthy high-risk population.
OBJECTIVE
African Americans (AA) have been shown to have lower exercise capacities and a higher prevalence of related risk for cardiovascular disease (CVD) compared to European Americans (EA). Broad biopsychosocial models that may inform the design of ethnic-specific exercise programs have not been well examined. We thus examined exercise capacity and its biopsychosocial correlates in a healthy population of AA and EA at increased risk of CVD.


METHODS
Subjects underwent maximal graded treadmill testing with gated single-photon emission computed tomography (SPECT); exercise capacity was expressed in MET-minutes. Medical history, psychosocial variables, general well-being, physical activity, and anthropometrics were assessed. Peak filling rate, a measure of left ventricular function, and ejection fraction were obtained from SPECT imaging, and the presence of silent ischemia was determined from the treadmill and SPECT imaging.


RESULTS
The sample (N = 1054) was 47% AA and 60% female. Mean age was 52.1 ± 9 yr for AA and 49.9 ± 10 yr for EA. Body mass index (BMI) was 32.5 ± 6.7 kg·m(-2) for AA and 29 ± 5.3 kg·m(-2) for EA. AA achieved a mean maximal exercise level of 31 MET·min less than EA did. In separate regression models by race, BMI (r(2) = 0 .30), age (r(2) = 0 .07), and sex (r(2) = 0 .03) explained 40% of the variance in MET-minutes in AA and 36% in EA, with a similar hierarchy of associated variables. The remaining variables had minimal effect on exercise capacity in either group.


CONCLUSIONS
BMI, older age, and female sex together contribute most to exercise capacity in both ethnicities. Hypothetically important biopsychosocial variables that may help shape ethnic-specific exercise programs add little to the prediction of exercise capacity. Thus, programs designed to reduce disparities in exercise capacity still need to first and foremost be geared to the age and sex demographics and address obesity.
Division of General Internal Medicine, Johns Hopkins Medical Institutions, Baltimore,MD 21287, USA. rbrown86@jhmi.edu
Rochelle V
RV
Brown
Brian G
BG
Kral
Lisa R
LR
Yanek
Dhananjay
D
Vaidya
Paul A
PA
Nyquist
David M
DM
Levine
Taryn F
TF
Moy
Lewis C
LC
Becker
Diane M
DM
Becker
D001741:Black or African American / Q000523:psychology; D000367:Age Factors; D000704:Analysis of Variance; D000886:Anthropometry; D015992:Body Mass Index; D016009:Chi-Square Distribution; D005080:Exercise Test; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D012737:Sex Factors; D011795:Surveys and Questionnaires; D015899:Tomography, Emission-Computed, Single-Photon; D044465:White People / Q000523:psychology