Effects of acute and 2-hour postphysical activity on the estimation of body fat made by the bod pod

The Bod Pod has been found to be reliable/valid against several criterion methods, including hydrostatic weighing and dual-energy x-ray absorptiometry, and under different conditions, such as clothing, dehydrated states, and body temperature changes. However, questions remain regarding the effects of an acute bout of exercise. Therefore, the purpose was to determine the effects of an acute bout of exercise on the estimations made by the Bod Pod. Participants (15 men and 22 women) were of age 18-27 years and were currently exercising. Baseline Bod Pod measures were completed followed by a 30-minute cycling trial at 75% of maximum heart rate. Bod Pod measures were taken immediately after exercise and 2 hours after exercise. Differences between men and women were found at baseline between height (p < 0.001), weight (p < 0.001), body volume (BV; p < 0.001), and body density (Db; p < 0.001). Among men, body mass (p < 0.001), body fat percentage (%BF; p < 0.001), and BV (p < 0.001) decreased, whereas Db (p < 0.001) and body temperature (p < 0.001) increased directly after exercise; body mass (p < 0.001) and BV (p < 0.001) remained lower after 2 hours. Among women, body mass (p < 0.001) and BV (p < 0.001) decreased, whereas thoracic gas volume (p = 0.014) and temperature (p < 0.001) increased directly after exercise; body mass (p < 0.001) and BV (p < 0.001) remained lower, whereas %BF (p < 0.001) and Db (p = 0.006) remained higher 2 hours after exercise. These results suggest that a single bout of exercise immediately before Bod Pod testing seems to alter the estimate of %BF, and continues to affect the prediction 2 hours after exercise in women.