Role of cardiorespiratory fitness and obesity on hemodynamic responses in children

Aim. The purpose of this study was to examine the effects of cardiorespiratory fitness (CRF) and obesity on arterial blood pressure and its determinants at rest and during isometric handgrip exercise (IHG) in children. Methods. Fourty-eight healthy children aged 11.6±0.3 (mean ±SE) years, (24 obese or overweight [OB/OV]; 24 normal weight [NO]) participated in the study. Both groups were divided into fit or unfit subgroups according to children's performance of an exercise test (PWC ₁₇₀). Arterial pressure and its determinants were recorded with the use of a photoplethysmographic device (FINOMETER) during 5 minutes of rest and 3 minutes of IHG at 30% of maximum voluntary contraction. Results. At rest and during IHG, unfit OB/OV children had higher systolic, mean arterial pressure, and rate pressure product (P≤0.05) than fit OB/OV children whose responses were similar to NO children, fit or unfit. Changes from rest, in cardiac output, cardiac index, and stroke volume were higher in unfit than in fit OB/OV children (P≤0.05). Unfit OB/ OV children exceeded their fit counterparts in several anthropometric measures. However, CRF was found to have a main effect on systolic blood pressure (P=0.05). Conclusion. Unfit versus fit OB/OV children had an exaggerated systolic blood pressure response at rest and during sympathetic activation, presumably coupled with higher cardiac output and cardiac oxygen demand. These results highlight the importance of fitness for health maintenance in obese and overweight children.