Study aim: Numerous data have indicated that body fat stores undergo complicated regulation by genetic and environmental factors, including physical activity. However, the majority of studies did not take into account this aspect of lifestyle in proposed body fat limits. In this context it seems that a more precise and reliable classification of body fat is provided by the American Council on Exercise (ACE), which distinguishes individuals not only with respect to sex but also activity level.
Material and methods: A total of 793 students (312 sedentary and 481 active) volunteered to participate in the study. Among sedentary participants 147 were male and 165 female. Among active subjects 206 were male and 275 were female. Active subjects were engaged in different modes of physical activity according to the study program. In all participants body mass index (BMI) was calculated. In participants with BMI 18.5–24.9 and BMI ≥ 25 body fat was determined using four skinfold measurements. Thereafter participants were classified according to the percentage of body fat using ranges for males and females provided by the American Council on Exercise (ACE) (essential fat, athletes, fitness, average and obese fatness).
Results: None of the sedentary and active males with BMI 18.5–24.9 had high (obese) fat. In contrast, in sedentary males with BMI ≥ 25 16.4% were obese vs. 1.8% of obese active ones. In sedentary females BMI from 18.5 to 24.9 did not exclude obesity, which was found in 16.9% of participants. In sedentary females with BMI ≥ 25 most of the subjects (97.1%) were obese. In contrast, in active females with BMI ≥ 25 a similar percentage of participants had average and obese fat (53.3% and 46.7, respectively).
Discussion: Our study clearly demonstrated that BMI as a simple measure of body composition provides false information concerning true adiposity in physically active male and female students. A similar BMI did not exclude marked differences in the percentage of body fat in sedentary and active students.
