Background: Poor cardiovascular fitness (CVF) is a risk factor for obesity, as well as insulin resistance (IR), inflammation, and cardiovascular disease. We have previously shown that a school-based fitness curriculum can improve CVF, as well as IR and body composition in obese children. Whether such a program improves CVF, IR, and other health indicators in non-obese children is unresolved. Aim: To determine whether a school-based fitness program improves body composition, CVF, markers of inflammation (e.g. CRP, TNF-α, adiponectin), and insulin sensitivity in non-obese children. Study design: 35 non-obese middle school children with body mass index below the 95th percentile for age were enrolled in a 'fitness-oriented' gym class. Children underwent fasting evaluation of insulin, glucose, adiponectin, CRP, TNF-α, body composition by dual X-ray absorptiometry (DXA), and maximal VO2 treadmill testing at baseline (prior to the school year) and again at end of the school year. Main outcome measures: Testing for CVF (maximal VO2 treadmill testing), DXA, and fasting evaluation of insulin, glucose, adiponectin, CRP and TNF-α. Results: Children demonstrated a decrease in BMI z-score (-0.14 ± 0.33, p = 0.02), HOMA-IR (-0.15 ± 0.35, p = 0.016), and TNF-α (-2.55 ± 1.79 pg/ml, p <0.001), and an increase in VO2max (+1.58 ± 2.34 ml/kg/min, p <0.001), adiponectin (+7,553 ± 11,100 ng/ml, p<0.001), and muscle mass (+2,282 ± 1,882.73 g, p<0.001) after nine months of study. Conclusions: The school-based fitness oriented curriculum resulted in improved body composition and insulin sensitivity, increased CVF, and decreased inflammation in non-obese children. Combined with prior studies, these data demonstrate that school-based fitness curricula can benefit both obese and non-obese children. Partnerships with schools to promote fitness should be part of a public health approach to improving children's health.
- Insulin resistance