Energetic cost and preferred speed of walking in obese vs. normal weight women.
OBJECTIVE
We tested the hypotheses that walking is more expensive for obese women, and they prefer slower walking speeds that minimize the gross energy cost per distance despite a greater relative aerobic effort [percent of maximal oxygen uptake (Vo(2max))/kg].


METHODS
Twenty adult women, 10 obese (BMI = 34.1 +/- 3.2 kg/m(2)) and 10 normal weight (BMI = 20.4 +/- 2.1 kg/m(2)) volunteered. To determine the metabolic rate and energy cost per distance vs. speed relationships, we measured Vo(2) and V(CO(2)) while subjects walked on a treadmill at six speeds (0.50, 0.75, 1.0, 1.25, 1.5, and 1.75 m/s; 5-minute trials, with a 5-minute rest period between trials). We measured preferred walking speed on a 50-m section of level sidewalk and Vo(2max) using a modified Balke treadmill protocol.


RESULTS
Walking was 11% more expensive for the obese subjects, but they preferred to walk at similar speeds as normal weight subjects (1.40 vs. 1.47 m/s, p = 0.07). Both groups preferred walking speeds at which their gross energy cost per distance was almost minimized. Obese subjects had a smaller Vo(2max)/kg, so they required a greater relative aerobic effort at the preferred speed (51% vs. 36%, p = 0.001).


CONCLUSIONS
Obese women preferred a walking speed that minimized energy cost per distance, even though this strategy required a greater relative aerobic effort than walking more slowly. Our results suggest that walking slower for a set distance may be an appropriate exercise recommendation for a weight management prescription in obese adults.
Browning
Raymond C
RC
Department of Integrative Physiology, 354 UCB, University of Colorado, Boulder, CO 80309, USA. raymond.browning@colorado.edu
Kram
Rodger
R
D000328:Adult; D001481:Basal Metabolism; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D009765:Obesity / Q000378:metabolism*; D010101:Oxygen Consumption; D012044:Regression Analysis; D016138:Walking / Q000502:physiology*