Fisieke aktiwiteit en insuliensensitiwiteit by swart kinders

Abstract

The increased prevalence of obesity amongst adolescents is considered a worldwide epidemic. Within the black population of South Africa, obesity is significantly more prevalent amongst black girls than black boys. The high prevalence of obesity amongst children can be attributed to a combination of various lifestyle factors, namely a decrease in physical activity, an increase in television viewing, Westernization and increased food supply. The decrease in physical activity amongst adolescents over the last few decades has led to an increase in the number adolescents diagnosed with type 2 diabetes mellitus. Research has indicated that insulin sensitivity improves with regular physical endurance activity, irrespective of change in body weight. Regular physical exercise also lowers the risk of type 2 diabetes mellitus, and prevents the development of coronary heart diseases, hypertension and obesity. The primary goals of this study were two-fold: Firstly, to determine the relationship between BMI, percentage body fat and insulin sensitivity amongst black adolescents, and, secondly, to determine whether there exists a positive correlation between current cardiovascular fitness (V02-maximum), together with everyday physical activity status, and insulin sensitivity amongst black adolescents. One hundred and twenty-four (124) black boys and 148 black girls between the ages of 14 and 17 participated in the study. The BOD-POD was used to calculate percentage body fat, and blood analysis for fasting glucose and insulin were completed. Insulin sensitivity (QUIKI-index) and resistance (HOMA) were also calculated, and habitual physical activity was measured using the "Previous Day Physical Activity Recall" (pDPAR) questionnaire. Physical development was determined with the Tanner questionnaire, cardiovascular fitness (VO2-maximum) was determined using the "Bleep" test and anthropometry (mass, length, skin folds, waist and hip circumference) was measured to determine body composition. The results of this study found a statistically significant negative correlation between skin fold thickness, percentage body fat, BMI and insulin sensitivity in girls. A significant negative correlation between percentage body fat and V02-maximum was found in boys, while their self-reported activity (PDPAR) did not correlate with percentage body fat. Current cardiovascular fitness and habitual physical activity status (PDPAR) showed no significant relationship with insulin sensitivity. Amongst the girls there was however a tendency towards a positive correlation between insulin sensitivity and V02-maximum.