Maintaining femoral bone density in adults: how many steps per day are enough?

Summary The amount and intensity of walking to maintain a healthy skeleton is unknown. This study examined the relationship between habitual walking activity and femoral bone mineral density (BMD) in healthy individuals using a quantitative theory for bone maintenance. Our results suggest a gender, weight, and speed sensitivity of walking interventions. Introduction Walking has been extensively promoted for the prevention of osteoporosis. The amount and intensity of walking to maintain a healthy skeleton is unknown and evidence to support a specific target of steps per day is lacking. The goal of our study was to examine the relationship between habitual walking activity and femoral bone mineral density (BMD) in healthy individuals using a quantitative theory for bone maintenance. Methods Habitual walking activity and total femur BMD were measured in 105 individuals (49–64 years). An index of cumulative loading (bone density index, BDI) was examined as a predictor of BMD. The BDI–BMD relationship was used to predict the steps per day to maintain healthy BMD values for a range of body weights (BW) and walking speeds. Results For females but not for males, BDI was correlated with BMD ( r 2 = 0.19, p