Comparing Energy Expenditure During Land and Shallow Water Walking in Overweight and Obese Women

Abstract

Physical activity is an important behavior for overweight and obese individuals. Aquatic exercise, including shallow water walking, is a popular form of aerobic activity in this population not requiring swimming skill. Although it has been shown to provide metabolic, cardiovascular, and psychological benefits, few studies have compared the responses to this form of exercise to land-based exercise. PURPOSE: To compare the energy expenditure (kcal/min) of a bout of shallow water walking to bouts of land walking in overweight and obese women. METHODS: Nineteen women (42.11 ± 10.30 yrs; 30.91 ± 3.78 kg/m2) completed three 10-minute trials including: a 1) shallow water walking at a self-selected pace; 2) land walking matched (± 10bpm) to the HR response of the shallow water walking bout; and 3) land walking at a self-selected pace. Oxygen uptake (mL·kg-1·min-1), ventilation (L·min-1), and respiratory exchange ratio (RER) were collected using a portable metabolic unit adapted for use in water. RESULTS: Results showed no difference in energy expenditure between shallow water (6.46 ± 1.38 kcal/min) and land walking (6.92 ± 1.61 kcal/min) at self-selected paces. However, significantly lower energy expenditure (p= 0.046) was observed for shallow water walking compared to matched HR response land walking (7.26 ± 1.29 kcal/min). When the difference in relative energy expenditure (kcal/kg/min) between shallow water walking and the matched HR response land walking was correlated with BMI and percent body fat, a moderate relationship was shown (r= 0.551, p= 0.014; and r= 0.556, p= 0.013) suggesting that the difference was reduced at higher levels of BMI and percent body fat. There were no correlations observed between body composition and differences in energy expenditure between shallow water and land walking at a self-selected pace. CONCLUSIONS: Findings suggest that shallow water walking is a viable alternative to land walking and can elicit an increase in energy expenditure performed at a moderate intensity in overweight/obese women. Since the difference in shallow water vs. land-based energy expenditure was reduced at higher levels of BMI and percent body fat, future studies should examine whether there is a threshold of obesity or body fatness that alters the response to water exercise compared to land-based exercise.