Exercise during radiation may keep anemia at bay

NEW YORK (Reuters Health) - A moderate-intensity program of brisk walking improves fitness and maintains hemoglobin levels in women undergoing radiation therapy after breast cancer surgery, a team of doctors has found.

It's known that aerobic exercise helps preserve red blood cells during the rehabilitation phase after chemotherapy treatments. How that translates to women undergoing radiotherapy had not been studied.

To find out, Dr. Jacqueline S. Drouin, from the University of Michigan-Flint, and colleagues recruited women who had been treated surgically for breast cancer and were undergoing radiation therapy 5 days per week for 7 weeks. Thirteen patients were randomly assigned to the aerobic exercise group and eight to flexibility training (placebo).

"The aerobic exercise protocol consisted of walking for 20 to 45 minutes 3 to 5 days per week during 7 weeks of radiation, at an intensity of 50 percent to 70 percent of each individual's measured maximum heart rate," the authors report. The control subjects performed stretching exercises under the same schedule.

Increases in red blood cell counts, levels of hemoglobin (the oxygen-carrying molecule in blood), and hematocrit (the volume of red blood cells) were observed in the women who actively exercised, although the changes were not statistically significant.

However, among women in the placebo-stretching group, all three measures declined significantly from baseline, so that differences between groups were significant.

For example, hemoglobin increased from 12.3 to 12.4 g/dL in the aerobic exercise group and declined from12.25 to 11.77 g/dL in the control group. The between-group difference was significant.

Drouin and colleagues observed that physical fitness, as measured by peak aerobic capacity, increased significantly only among patients participating in aerobic exercise, and that peak aerobic capacity correlated positively with the final red blood cell counts, hemoglobin levels and hematocrits.

SOURCE: Cancer, November 15, 2006.