Abstract P138: The Association of a Greater Step Count with Body Composition in Young Adults

Abstract

Introduction: Walking has been associated with a reduction of cardiovascular disease risk, but there remains limited information on the association between volume of steps and body composition. Therefore, the purpose of this study is to examine the association between the number of steps per day and percent body fat in young, generally healthy adults. Hypothesis: It is hypothesized that those with a greater number of steps per day will have a decreased percent body fat, compared to those who spend more time in sedentary behavior. Methods: A sample of 418 young adults (49% male), between the ages of 21 and 35 and a body mass index (BMI) between 20 and 35 kg/m2 provided valid objective activity data. Participants were given a SenseWear mini armband to wear for ten days with compliance set at 7 days of wear time, including 2 weekend days, with at least 21 hours of verifiable time per day. Step count was averaged per day based off the total days of armband wear. In addition, participants completed a dual x-ray absorptiometry scan to measure fat mass and fat free mass, percent body fat (BF) was then calculated. Results: The average BMI of the sample was 25.3 kg/m2 with a percent body fat of 22.5% and 34.1% for males and females, respectively. Males had higher step counts than females (p=.005). Quintiles were created based off average steps per day (±SD) (mean values for least steps to most steps: 4051 ± 336; 4503 ± 800; 7286 ± 360; 8544 ± 436; 12,011 ± 2,140). There was a linear trend across quintiles (p for trend < .01) of decreasing percent body fat with increased steps, after adjusting for age and sex. No significant difference between step quintiles was observed for BMI (p for trend = .06) after adjusting for the same covariates. Results were similar when analyzing males and females separately. Conclusion: In conclusion, these results indicate that a higher step count is associated with lower BF. Given that percent body fat is associated with various health outcomes and the fact that walking is an inexpensive and feasible activity for most populations, further efforts are needed to increase steps/day in US adults.