Impact of high- and low-intensity targeted exercise training on the type of substrate utilization in obese boys submitted to a hypocaloric diet

Carbohydrate and fat metabolism related to blood lactate in boys and male adolescents

“…2) are consistent with current concepts of the regulation of CHO and FAO, and pyruvate and lactate and their appearance in the blood compartment during exercise (Beneke 2003a;Brooks and Mercier 1994;Conley et al 1998;Spriet and Heigenhauser 2002;Strumilo 2005). They seem to be also supported by previous findings that describe the acute response to be exercise based on an individual's dynamic changes in respiratory and/or BLC measurements such as the crossover point and the MLSS.…”

“…According to the crossover concept (Brooks and Mercier 1994), at low exercise intensity energy metabolism relies predominantly on the oxidation of fatty acids (FAO). The glycolytic rate increases with exercise intensity and lactate and pyruvate are produced in, consumed by and exchanged between different tissues and cells (Henderson et al 2004).…”

“…1). Aerobic carbohydrate combustion (CHO) exceeds FAO as metabolic rate increases (Brooks and Mercier 1994). In the severe exercise intensity domain, BLC and pyruvate availability increase more rapidly and CHO seems to comprise nearly 100% of the aerobic metabolic rate, and the relative rate of carbohydrate combustion (relCHO) approaches saturation (Fig.…”

Measurement and Physiological Relevance of the Maximal Lipid Oxidation Rate During Exercise (LIPOXmax)

“…The maximal fat oxidation rate (MFO) has been expressed in mg/min (Perez-Martin & Mercier, 2001;Dumortier et al, 2002;Brandou et al, 2003Brandou et al, , 2005Brandou et al, , 2006aBrandou et al, , 2006b), g/min (Achten et al, 2003;Achten & Jeukendrup, 2004;Jeukendrup, 2003), mg/min/kg body weight, mg/min/kg fat free mass, and more recently in mg/min/kg muscle mass (Lavault et al, 2011). Muscle can be evaluated from bioimpedance analysis with a validated equation (Janssen et al, 2000), and expression of MFO in mg/min/kg muscle offers at least two advantages: it helps to delineate the effects of training on muscle mass and on the ability of www.intechopen.com Measurement and Physiological Relevance of the Maximal Lipid Oxidation Rate During Exercise (LIPOXmax) 11 each kg of muscle to burn lipids; it provides an index which has been shown to be predictive of the effects of exercise on weight loss (Lavault et al, 2011) as indicated below.…”

“…This is a constant finding, while protocols using higher intensities in patients give less consistent result on fat-free mass (Brandou et al, 2005;. Obviously, it is well demonstrated that correctly performed resistance training is an efficient way to improve fat free mass (Schoenfeld et al, 2010), but low intensity exercise has also been demonstrated to protect lean mass and to prevent protein breakdown.…”