Effects Of Aerobic Training On Determinants Of Peak Oxygen Consumption In Post-treatment Breast Cancer

PURPOSE: Breast cancer (BC) therapy causes marked impairments in peak oxygen consumption (VO2peak), predisposing patients to elevated risk of cardiovascular morbidity and mortality. The determinants of impaired VO2peak and the effects of aerobic training (AT) on these determinants in post-treatment BC are not known. METHODS: Individual participant data from two randomized AT trials [(1) women at high risk of BC (BC risk; n = 24), (2) women 1-5 years post-treatment (n = 30)] were included. VO2peak and peak cardiac output (Q) were evaluated in women randomized to AT using identical treadmill-based peak cardiopulmonary and echocardiography exercise testing protocols before and after 12 (BC risk) or 16 weeks (post-treatment) of 150 min/wk of non-linear supervised AT. Arterial-venous oxygen content difference (a-vO2 Diff) was calculated using the Fick equation (VO2peak divided by Q). RESULTS: At baseline, relative to BC risk (mean age ± SD, 56.9 ± 9.3 years) post-treatment (61.3 ± 8.3 years) had lower VO2peak (post-treatment: 19.8 ± 3.8 ml O2·kg-1·min vs. 25.9 ± 4.7 ml O2·kg-1·min; p < 0.01). Peak Q was lower in post-treatment (14.5 ± 1.8 L/min) relative to BC risk (16.3 ± 2.3 L/min, p < 0.05); there were no significant differences in a-vO2 Diff. After AT, VO2peak improved in post-treatment (1.2 ± 1.7 ml O2·kg-1·min) and BC risk (2.5 ± 2.6 ml O2·kg-1·min). Peak a-vO2 Diff increased in both BC risk (0.8 ± 1.6 mL/dL) and post-treatment (0.8 ± 1.7 mL/dL). Peak Q increased in BC-risk (0.4 ± 2.0 L/min) and decreased in post-treatment (-0.1 ± 2.3 L/min). CONCLUSIONS: Aerobic training improves peak a-vO2 Diff but not peak cardiac output in post-treatment BC. These findings suggest that AT volume greater than 150 min/wk may be needed to induce cardiovascular improvements and further augment VO2peak response in post-treatment BC. 3U01CA271287-02S1