Association of Anthropometric Obesity Measures with Physical Fitness in Adolescents: A Cross-sectional Comparative Study

Obesity is increasing in Saudi Arabia at an alarming rate being ranked 29 th on a 2007 list of the fattest countries. Childhood/ adolescent obesity is a risk factor for cardiovascular disease and metabolic syndrome (MS) in adulthood and thus affects morbidity and mortality. Obesity also affects the cardiorespiratory and overall physical condition. Therefore, this study was aimed to evaluate if early obesity in life has a prediction of worse cardiac function and their association with cardiorespiratory physical fitness. This cross-sectional study included 90 adolescents with matched sex and age 14(2) years were divided into three groups-1) Normal weight (NW), 2) Overweight (OW) and 3) Obese (OB) based on the BMI (body mass index) percentile for age and sex. Their waist circumference, waist-height ratio (WHtR), resting pulse rate and blood pressure were measured by standardized laboratory techniques. The modified Harvard step test was used to assess the physical fitness index (PFI %) rated as excellent, good, fair and poor based on score. The obesity, cardiovascular and physical fitness parameters were compared between groups using Mann Whitney U test and the association between obesity and physical fitness parameters were evaluated by Spearman correlation test using SPSS V.20. The cardiovascular parameters-the pulse rate (NW Vs OW: 80(9)-89.5(13)/min, p < 0.001; and NW Vs OB: 80(9) -94(12)/min, p < 0.001), SBP (NW Vs OW:117(5) -120(9) mmHg, p=0.003; and NW Vs OB:117(5) -121(9) mmHg, p < 0.001) and DBP (NW Vs OW: 74.33 3.64 -79.43 5.54 mmHg, p < 0.001; and NW Vs OB:74.33 3.64 -81.20 3.91 mmHg, p < 0.001) were statistically significant between NW Vs OW and NW Vs OB groups. The physical fitness index level is statistically significant among NW Vs OW [1(1)-2.5(1), p < 0.001], NW Vs OB [1(1)-4(0), P < 0.001]. The obesity measures-BMI/BMI percentiles were inversely related to the physical fitness score (rho=-0.589, p < 0.001), WC (rho=-0.565, p < 0.001) and WHtR ((rho=-0.565, p < 0.001). This study revealed poor cardiovascular measures with increased resting heart rate and blood pressure and the inverse association between cardiovascular physical fitness and obesity measures in the adolescent.