Exercise can slow bone loss in breast-feeding mothers

Study finds women who do resistance and aerobic training lose less bone mineral density

THURSDAY, Oct. 1 (HealthDay News)-Breast-feeding mothers who engage in resistance and aerobic exercise lose less bone mineral density than their sedentary counterparts do, according to a study in the October issue of

Medicine & Science in Sports & Exercise

.

Cheryl A. Lovelady, Ph.D., a registered dietician at the University of North Carolina in Greensboro, and colleagues conducted a study of 20 exclusively breast-feeding mothers four weeks postpartum, of whom 10 were randomized to three days a week of resistance and aerobic exercise for 16 weeks, while the remaining 10 women formed the control group and did not exercise.

After 16 weeks, the researchers measured lumbar spine bone mineral density and found that women in the exercise group lost only 4.8 percent, compared to 7.0 percent for the control group, but that there were no significant differences in total body and hip bone mineral density. While both groups lost fat mass, the exercise group lost less lean body mass, the investigators discovered.

"The lumbar spine is composed of highly metabolic trabecular bone, which has a much higher turnover rate, as compared with the whole body, and is more susceptible to rapid mineralization and losses," the authors write. "To our knowledge, this is the first published study to investigate the effects of both resistance and aerobic exercises on bone mineral density in a randomized study of exclusively breast-feeding women."

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