Increased snacking calories, frequency, and evening snacking are independently associated with overweight/obesity in Italian middle-school adolescents.

Physical exercise is associated with increases of serum and salivary levels of cortisol. The concomitant increase in serum lactate has been implicated as one of the mechanisms responsible for adrenocortical activation. We evaluated the responses of serum lactate and serum and salivary cortisol to an acute bout of high-intensity isokinetic exercise in eleven non-competitive and twenty competitive athletes (NCA and CA, respectively). The latter group was composed of endurance- and power-trained athletes (EA and PA, respectively). Aims of the study were to determine interindividual differences in the lactate and cortisol responses as a function of type and intensity of training and to search for relationships both between lactate and cortisol production and between serum and salivary cortisol levels. The isokinetic exercise test elicited significant cortisol and lactate responses. No difference was evident in the lactate responses between NCA and CA, while the PA showed a higher response during and after the exercise in comparison to EA (peak levels immediately after the exercise: PA 15.0 +/- 1.5 mmol/l vs. EA 11.1 +/- 2.6 mmol/l, p < 0.01). Serum cortisol was higher in the CA in comparison to the NCA group at 30 and 120 minutes after the termination of the exercise, while no differential response was evident between EA and PA groups. Salivary cortisol response was higher in the CA group in comparison to NCA immediately after the exercise and at 90 and 120 minutes after the termination and was higher in PA in comparison to EA at 60, 90, and 120 minutes after the termination (peak levels at 60 minutes: PA 51.2 +/- 18.5 nmol/l vs. EA 27.5 +/- 20.8 nmol/l, p < 0.05). No significant correlations were found between serum or salivary cortisol and lactate levels. The relationship between serum and salivary cortisol was markedly non-linear, the slope of the serum-saliva regression line being lower for serum cortisol concentrations over 500 nmol/l than for concentrations below that value (0.019 and 0.037, respectively, p < 0.01). We have confirmed in this particular setting the existence of an important adrenocortical response that can be reliably and non invasively assessed by a serial saliva sampling and have supported the concept that cortisol and lactate responses to a high-intensity isokinetic exercise are independent. The interindividual differences in cortisol changes are likely to be related to the training status and mode as well as to the correspondence between the evaluation protocol and the discipline individually performed.

Seven healthy young male adults were subjected to a total of 56 tests to ascertain the effects of L-carnitine (L-C) and a placebo (P) on ventilation, O2 intake (VO2), CO2 output, heart rate, blood pressure and serum lactic acid, non-esterified fatty acid, glycerol and glucose during strenuous and aerobic/anaerobic threshold-level treadmill exercise. The tests were made in conditions of normoxia (O2 = 20.9%) and hypoxia (O2 = 13.0%, equivalent to 3,500 m above sea level). The only clear difference was in the respiratory quotient (RQ = 0.883, SD 0.025 vs 0.904, SD 0.035) after L-C and P administration respectively (P less than 0.01), under normal oxygenation and 0.861, SD 0.052 following L-C vs 0.926, SD 0.040 after P (P less than 0.01) in acute hypoxia at VO2 levels around the anaerobic threshold. The lower RQ values of the L-C-treated subjects during hypoxia indicate a lower rate of carbohydrate transformation.

Background/objectives: The relationship between sodium intake and arterial blood pressure (BP)

Exercise stimulates the release of interleukin-6 (IL-6). Aims of the study were to: (a) analyse the IL-6 response to exercise in power (n = 7) and endurance athletes (n = 13); (b) determine the effects of the IL-6 production on mechanical and myoelectric fatigue; (c) evaluate the relationship between IL-6 and adrenocortical responses. EMG variables (conduction velocity, mean power frequency, average rectified value), ACTH, cortisol, DHEA, IL-6, myoglobin, and lactate were analysed before and after an isokinetic exercise. The exercise elicited significant mechanical and myoelectric fatigue as well as significant biochemical responses. Power athletes showed IL-6 and lactate responses higher than endurance athletes. The correlation analyses showed that the greater the mechanical fatigue, the greater the increases in lactate and IL-6. No correlations were found between IL-6 and EMG variables. No relationships were found between IL-6 and cortisol, after correction for ACTH levels. In conclusion, the muscular IL-6 production, as inferred by its circulating levels, had no detectable effects on the myoelectric manifestations of fatigue and the cortisol response to exercise was not related to the amount of circulating IL-6, but only to the activation of ACTH secretion.

The use of local charts seems more appropriate at least in Italian adolescents in the age range studied.

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