The relationship between pedometer-determined ambulatory activity and bodycomposition variables

OBJECTIVE: To examine the relationship between pedometer-determined ambulat ory activity (steps/day) and body composition variables body mass index (BM I) and percentage body fat). DESIGN: Secondary analysis of a cross-sectional objective activity monitori ng study for up to 21 consecutive days. SUBJECTS: A total of 109 apparently healthy adults (eight African American males, 23 African-American females, 33 Caucasian males, 45 Caucasian female s), age 44.9 +/- 15.8 y, BMI = 26.9 +/- 5.1 kg /m(2). MEASUREMENTS: Pedometer-assessed ambulatory activity (steps/day), height an d weight, and percentage body fat by bioelectrical impedance. RESULTS: Analyzed as both a continuous and a categorical variable (determin ed using 25th and 75th percentiles for distribution for steps/day), ambulat ory activity was consistently related to body composition variables. Steps/ day was inversely correlated with BMI and percentage body fat (r = -0.30, a nd r = -0.27, respectively, both P < 0.01). The consistency of the relation ship was also evident when examined using accepted BMI cut-off points for n ormal-weight, overweight, and obese categories. CONCLUSIONS: Individuals in this small sample with values greater than appr oximately 9000 steps/day are more frequently classified as normal weight fo r height. Individuals with values less than approximately 5000 steps/day ar e more frequently classified as obese. These findings require further corro borative investigation but provide preliminary cutoff points for identifyin g individuals at risk who may benefit from appropriate physical activity in tervention.