Five-year maintenance of bone mineral density in women master runners

Prior research has suggested that chronic running may not prevent age-related bone loss in women and may inhibit the influence of hormone replacement therapy (HRT) on bone. The purpose of this study was to longitudinally determine the effect of chronic running exercise alone, and in conjunction with HRT, on bone mineral density (BMD) in premenopausal and postmenopausal women.

Forty-one women runners were tested an average of 4.8 yr apart, and separated into four groups according to their menstrual and HRT status at both test 1 and test 2. Measurements included BMD, body composition, and VO2(max), as well as training, menstrual, and nutritional histories. Factorial and one-way ANOVA were used for analysis.

Group differences existed for body mass and body composition but did not change over time. Fitness and training variables were not different by group or time. Calcium intake did not differ between groups, but increased over time (829 +/- 310 vs 1058 +/- 468 mg.d (-1). BMD of the hip, spine, and whole body were different between groups but did not change significantly over time. Regression analysis revealed age as the only significant predictor of change in bone mass.

These data demonstrate no significant loss of bone mass over a 5-yr period in these chronic runners with relatively high calcium intakes regardless of menstrual or HRT status. Further, chronic running did not inhibit nor enhance the effect of HRT on bone in these women.