Study objectives: To determine the factors associated with exercise capacity.
Design: Retrospective evaluation of large stress-testing database.
Setting: Multispecialty tertiary care center.
Patients: A total of 5,069 consecutive patients who were referred for exercise stress testing.
Measurements: We compared levels of fitness in 641 African-Americans (52% male) with 4,428 whites (73% male), and performed univariate and multivariate analyses to determine the predictors of fitness (including race).
Results: Compared with African-American men (mean [+/- SD] age, 60 +/- 11 years), white men (mean age, 63 +/- 11 years) have significantly higher exercise capacity (10.7 +/- 3.5 vs 11.4 +/- 3.4 metabolic equivalents [METs], respectively; p < 0.001). The exercise capacity in African-American and white women was similar (8.5 +/- 2.9 vs 8.7 +/- 3.0 METs, respectively). However, body mass indexes (BMIs) were significantly higher in both African-American men (29.1 +/- 4.3 vs 28.2 +/- 4.3 kg/m(2), respectively; p < 0.001) and women (30.2 +/- 5.7 vs 27.9 +/- 5.5 kg/m(2), respectively; p < 0.0001) compared to their white counterparts, as was the prevalence of obesity (men, 44% vs 33%, respectively; women, 37% vs 27%, respectively; both p < 0.001). Although a model containing age, gender, BMI, and race only accounted for 32% of exercise capacity, all independently (p < 0.0001) predicted higher exercise capacity, as follows: younger age (r(2) = 0.14); male gender (r(2) = 0.12); BMI (r(2) = 0.06); and white race (r(2) = 0.004).
Conclusions: In an adult population of individuals who were referred for exercise stress testing, African-Americans were more obese and had significantly lower exercise capacity than their white counterparts. Emphasis on weight reduction and increasing physical fitness is particularly needed for the prevention of cardiovascular diseases in African-Americans.