MODERATE PHYSICAL ACTIVITY CORRELATES WITH ELEVATED LEPTIN IN PHYSICALLY ACTIVE 10–12-YEAR-OLD BOYS WITH NORMAL BMI

The aim of this study is to examine the relations between physical activity of diff ering intensity and duration with body energy-balance hormone leptin in 10–12-year-old boys ( N = 94) who participated in moderate-to-vigorous physical activity at least four to fi ve times per week. The boys reported their physical activity using a questionnaire. They had normal body mass index (BMI, kg/ m 2 ), and were at Tanner Stage 2 of development. Boys were divided into three subgroups by leptin levels: normal serum leptin ( M ± .5 SD, n = 44, 1.2–3.9 ng/ml), low leptin (≤ M – .5 SD; n = 31, < 1.2 ng/ml), and high leptin (≥ M + .5 SD ; n = 19, > 3.9 ng/ml). There were signifi cant diff erences between subgroups in anthropometric parameters and serum leptin levels, but not in physical activity. A significant correlation was found between leptin and moderate physical activity of at least fi ve times per week for at least 30 minutes each time in the high leptin group ( r = .61). In conclusion, the correlations between physical activity and leptin are weak; only moderate physical activity was correlated with leptin levels in the high leptin group.