Random control clinical trial on the effects of aerobic exercise training on erythrocyte levels during radiation treatment for breast cancer

BACKGROUND. Erythrocyte changes from aerobic exercise training were examined during radiation treatment of breast cancer. METHODS. Twenty sedentary females with breast carcinoma who were ages 35 to 65 years were randomized to aerobic exercise (AE) of walking for 20 to 45 minutes, 3 to 5 times per week, at 50% to 70% of measured maximum heart rates or to placebo stretching (PS) activities 3 to 5 days per week during 7 weeks of radiation treatment. Measures were obtained 1 week before and after the radiation regimen. Serum blood analyses, through complete blood counts, measured red blood cell counts (RBC), hematocrit (HCT), and hemoglobin (HB). Peak aerobic capacity (peak VO2) was measured by exercise testing with oxygen uptake analysis to assess training. A Wilcoxon Mann-Whitney U test examined changes between groups (P <= .05 for significance). RESULTS. AE peak VO2 increased by 6.3% (P = .001) and PS decreased by 4.6% (P = .083). RBC increased in AE from 4.10 to 4.21 million cells/mu L and declined in PS from 4.30 to 4.19 million cells/mu L; the between-group differences were significant (P = .014). HCT increased in AE from 38.0% to 38.8% and declined in PS from 37.40% to 36.50%; the between-group differences were significant (P = .046). HB increased in AE from 12.3 to 12.4 g/dL and declined in PS from 12.25 to 11.77 g/dL; the between-group differences were significant (P = .009). CONCLUSIONS. The results of the current study suggest that moderate intensity aerobic exercise appears to maintain erythrocyte levels during radiation treatment of breast cancer compared with the declines observed in nontraining individuals. These findings suggest a safe, economical method to improve fitness and maintain erythrocytes in women during radiation treatment of breast cancer.