Exercise dose-response of the V(E)/VCO(2) slope in postmenopausal women in the DREW study.
OBJECTIVE
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(E)/VCO(2) slope, which is predictive of mortality in patients with CHF. Although the V(E)/VCO(2) slope is well established in CHF patients, little is known regarding interventions for "at-risk" populations.


METHODS
We examined the V(E)/VCO(2) slope in 401 sedentary, overweight, moderately hypertensive women randomized to 6 m of nonexercise (control) or 4 kcal x kg(-1) x wk(-1) (KKW), 8 KKW, or 12 KKW of exercise at an intensity corresponding to 50% of baseline VO(2max). We examined trends in exercise treatment dose versus change in mean V(E)/VCO(2) slope using a linear regression model (KKW vs V(E)/VCO(2) slope) and a linear mixed model.


RESULTS
Regression analysis showed a significant trend for a reduction in the V(E)/VCO(2) slope from baseline (mean +/- SD: 32.6 +/- 6.3; P < 0.004). When expressed as mean change (95% confidence interval (CI)) from baseline, we observed significant reductions in the V(E)/VCO(2) slope for the 8-KKW (-1.14; 95% CI, -1.5 to -0.2) and 12-KKW (-1.67; 95% CI, -2.3 to -0.3) groups. No significant effect was noted for the 4-KKW (-0.4; 95% CI, -1.2 to 0.15) group.


CONCLUSIONS
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(E)/VCO(2) slope in postmenopausal women who exhibit risk factors associated with the development of CHF.
Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA.
Stephanie A
SA
Anaya
Timothy S
TS
Church
Steven N
SN
Blair
Jonathan N
JN
Myers
Conrad P
CP
Earnest
D000368:Aged; D001794:Blood Pressure; D002245:Carbon Dioxide / Q000032:analysis / Q000378:metabolism*; D015444:Exercise; D045853:Exhalation / Q000502:physiology*; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D016014:Linear Models; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D010809:Physical Fitness; D017698:Postmenopause; D040242:Risk Reduction Behavior
D002245:Carbon Dioxide