Exercise Dose-Response of the (V) over dotE/(V) over dotCO2 Slope in Postmenopausal Women in the DREW Study

ANAYA, S. A., T. S. CHURCH, S. N. BLAIR, J. N. MYERS, and C. P. EARNEST. Exercise Dose-Response of the (V) over dot(E)/(V) over dotCO(2) Slope in Postmenopausal Women in the DREW Study. Med, Sci. Sports Exerc., Vol. 41, No. 5, pp. 971-976, 2009. Purpose: Being overweight/obese, having hypertension, and being postmenopausal are risk factors for the development of congestive heart failure (CHF). A characteristic of CHF is an abnormal (V) over dot(E)/(V) over dotCO(2) Slope, which is predictive of mortality in patients with CHF. Although the (V) over dot(E)/(V) over dotCO(2), slope is well established in CHF patients, little is known regarding interventions for "at-risk" populations. Methods: We examined the (V) over dot(E)/(V) over dotCO(2) slope in 401 sedentary, overweight, moderately hypertensive women randomized to 6 m of nonexercise (control) or 4 kcal.kg(-1).wk(-1) (KKW), 8 KKW, or 12 KKW of exercise at an intensity corresponding to 50% of baseline (V) over dotO(2max). We examined trends in exercise treatment dose versus change in mean (V) over dot(E)/(V) over dotCO(2) slope using a linear regression model (KKW vs (V) over dot(E)/(V) over dotCO(2) slope) and a linear mixed model. Results: Regression analysis showed a significant trend for a reduction in the (V) over dot(E)/(V) over dotCO(2) slope from baseline (mean +/- SD: 32.6 +/- 6.3; P < 0.004). When expressed as mean change (95% confidence interval (Cl)) from baseline, we observed significant reductions in the (V) over dot(E)/(V) over dotCO(2), slope for the 8-KKW (- 1.14; 95% Cl, - 1.5 to -0.2) and 12-KKW (- 1.67; 95% Cl, -2.3 to -0.3) groups. No significant effect was noted for the 4-KKW (-0.4; 95% Cl, - 1.2 to 0.15) group. Conclusion: Moderate-intensity aerobic exercise at doses of 8 KKW or greater seems to present an adequate dose of exercise to promote small but significant reductions in the (V) over dot(E)/(V) over dotCO(2) Slope in postmenopausal women who exhibit risk factors associated with the development of CHF.