ESPE Abstracts

Background: Higher physical activity (PA) attenuates the health risks of obesity and has positive effects on body weight reduction. The results of our recent longitudinal study showed that PA, especially vigorous PA (VPA), is an important factor for predicting overweight in boys during puberty (Lätt et al., 2015).

Objective and hypotheses: The aim of this study was to examine the associations of fasting serum acylated and des-acylated ghrelin, peptide YY (PYY) and leptin levels with PA and cardiorespiratory fitness (CReF) parameters in adolescent overweight (OWB) and normal weight (NWB) boys.

Method: Fasting blood samples of 55 OWB (BMI >85th percentile) and 154 NWB (BMI <85th percentile) aged 12–16 years were collected to measure serum acylated and des-acyl ghrelin, PPY, leptin, testosterone, glycose, and insulin levels. Total PA was measured by 7-day accelerometry (counts/min) and CReF by direct measurement of peak oxygen consumption (VO₂ peak/kg).

Results: No differences were seen in serum PYY, acylated or des-acylated ghrelin levels, while mean leptin (11.6±10.6 vs 2.0±2.7 ng/ml) and insulin (18.1±8.7 vs 11.0±6.2 mU/l) were significantly higher (P<0.05) in OWB compared to NWB. CReF was significantly lower in OWB compared to NWB (39.7±8.7 vs 50.5±6.8 ml/min per kg; P<0.05). Leptin was negatively correlated with CReF in both groups (r=−0.43; P<0.05) and des-acylated ghrelin with CReF only in OWB (r=−0.36; P<0.05). In OWB leptin was negatively correlated with total PA (r=−0.32; P<0.05) and positively with sedentary time of PA (r=0.35; P<0.05). In NWB 28.1% of the variability of CreF was determined by leptin and insulin resistance index (HOMA-IR) whereas in OWB 71.9% was determined by trunk FM and BMI.

Conclusion: Serum leptin concentration is inversely associated with CReF in adolescent boys independently of their BMI value while serum des-acyl ghrelin may be involved to determine the CReF level in OWB. Low PA in OWB is associated with high serum leptin level.