Comparison of the Metabolic Cost of Walking in Obese and Normal Weight Adults

Information regarding the energetic cost of walking at preferred speed is important as societal increases in obesity status have risen over the past two decades. PURPOSE: The purpose of this study was to compare the metabolic cost of waking at preferred speed and 25% below & above preferred speed in obese (O) and normal weight (NW) adults. The design was modeled after the work of Browning & Kram, 2005. METHODS: Thirty one adults volunteered (14 O, 6M, 8F; 17 NW, 6M, 10F). Participants walked on the treadmill for five minutes each at preferred speed, 25% above and 25% below preferred speed. Metabolic rate (indirect caloric expenditure) was measured and the last two minutes of each condition were averaged. Net (N) values were obtained by subtracting standing ambulatory rest from gross (G) values. Body composition was determined via DXA. Statistical analysis included a two way ANOVA (group × condition) and significance was set at p < 0.05. RESULTS: Significantly greater body composition (mass, % fat and BMI) was found in O. No group differences were noted in preferred walking speed and net metabolic rate (W per kg). However group differences were noted for G & N VO2 (L/min), and N VO2 relative to FFW. Browning & Kram observed a significantly greater metabolic rate (W per kg) in O as compared to NW women. CONCLUSION: Including both genders in the current study and subjects who were only mildly to moderately obese may have led to a similar metabolic rates (W per kg) across obesity status.