9 research outputs found

    Biological aspects of salivary hormones in male half-marathon performance

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    Physical effort is known to alter the blood levels of many hormones, but there are only a few studies about the biological changes of salivary hormones. The aim of this work was to determine whether salivary testosterone and salivary cortisol levels, measured two weeks before a half-marathon race, relate to running performance in male recreational athletes. A group of eleven male recreational athletes preparing for a half-marathon was included in the study. Saliva for testosterone and cortisol determinations was collected before and immediately after a 15-km training run, two weeks before the half-marathon. Individual official half-marathon times, expressed in hours, were used as a measure of performance. Mean testosterone concentrations were 1.07±0.33 nmol/L before the run and 0.88±0.35 nmol/L after the run (p<0.05). Mean cortisol concentrations were 12.28±8.46 nmol/L before the run and 38.08±19.63 nmol/L after the run (p<0.05). The pre-run salivary testosterone levels marginally correlated with the corresponding half-marathon running times (p=0.068, 95% bootstrap CI for slope -0.40 to -0.06). However, post-run salivary testosterone levels significantly correlated with the corresponding half-marathon running times (p=0.011, 95% bootstrap CI for slope -0.41 to -0.16), even considering correlations with the runners’ age. Salivary cortisol levels, either pre- or post-run, did not correlate with the corresponding half-marathon running times. The results of this study suggest that post-exercise salivary testosterone levels could have the potential to predict performance in endurance running, at least in recreational athletes. [Projekat Ministarstva nauke Republike Srbije, br. 175036

    Glycogen phosphorylase isoenzyme BB plasma kinetics is not related to myocardial ischemia induced by exercise stress echo test

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    Background: Glycogen phosphorylase BB (GPBB) is released from cardiac cells during myocyte damage. Previous studies have shown contradictory results regarding the relation of enzyme release and reversible myocardial ischemia. The aim of this study was to determine the plasma kinetics of GPBB as a response to the exercise stress echocardiographic test (ESET), and to define the relationship between myocardial ischemia and enzyme plasma concentrations. Methods: We studied 46 consecutive patients undergoing ESET, with recent coronary angiography. In all patients, a submaximal stress echo test according to Bruce protocol was performed. Concentration of GPBB was measured in peripheral blood that was sampled 5 min before and 10, 30 and 60 min after ESET. Results: There was significant increase of GPBB concentration after the test (p=0.021). Significant increase was detected 30 min (34.9% increase, p=0.021) and 60 min (34.5% increase, p=0.016) after ESET. There was no significant effect of myocardial ischemia on GPBB concentrations (p=0.126), and no significant interaction between sampling intervals and myocardial ischemia, suggesting a similar release profile of GPBB in ischemic and non-ischemic conditions (p=0.558). Patients in whom ESET was terminated later (stages 4 or 5 of standard Bruce protocol; n=13) had higher GPBB concentrations than patients who terminated ESET earlier (stages 1, 2 or 3; n=33) (p=0.049). Baseline GPBB concentration was not correlated to any of the patients' demographic, clinical and hemodynamic characteristics. Conclusions: GPBB plasma concentration increases after ESET, and it is not related to inducible myocardial ischemia. However, it seems that GPBB release during ESET might be related to exercise load/duration

    Interpreting different measures of glomerular filtration rate in obesity and weight loss: pitfalls for the clinician

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    To combat the increasing incidence of obesity, much research has been devoted to devising successful strategies for weight loss, including manipulation of diet and gastric surgery. Obesity itself can be associated with renal dysfunction, and the degree of reversibility of this with weight loss has being studied. However, there are significant limitations and flaws in the methods we have available to measure glomerular filtration rate (GFR) in overweight and obese subjects. Obesity is associated with changes in body composition including lean and fat mass. This has implications for assumptions that underpin creatinine-based measures such as creatinine clearance, estimated GFR and other equations devised for obesity including the Salazar–Corcoran equation. These changes in body composition also affect measures of glomerular filtration such as cystatin C and nuclear medicine isotope scans. This article will review the accuracy of these current measures of renal function in the obese and consider the evidence for adjusting for body surface area or adjusting for lean body mass. Finally, the effect of weight loss itself on serial measurements of renal function in a given individual, independent of a true change in renal function, will be reviewed. Ultimately using the Cockcroft–Gault equation with an adjustment for lean body mass seems to be the best measure for renal function in obesity. No method for measuring renal function in situations of weight loss has been shown to be unequivocally superior.D.R. Jesudason and P. Clifto
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