Serum Creatinine Concentrations in Athletes: Are They Normal?

BANFI, G. Serum creatinine concentrations in athletes: are they normal? Brazilian Journal of Biomotricity, v. 4, n. 3, p 157-164, 2010. In sports medicine, creatinine is used for evaluating general health status of athletes. In the present review, different aspects of the behaviour of creatinine values in sportsmen are summarized. The reference values for common biochemical and haematological parameters used for athletes are the same commonly used for general population. The serum concentration of creatinine could sometimes apparently pathological in some athletes and the interpretation of these values should consider the sportsmen status. In fact, the values of serum creatinine in athletes are higher than those reported in sedentary people. However, the population of sportsmen is not homogeneous, and some differences are evident among athletes competing in different sport disciplines. The creatinine values are affected from acute exercise, which modifies renal flow. The sport discipline is an additional variable for interpreting creatinine values, which can show values lower than those measured in sedentary people in endurance athletes. The creatinine values are modified in some sport disciplines during competitive season, showing increases when activity is more intense. Cystatin C, a low molecular weight that is freely filtered through the glomerulus and almost completely reabsorbed and catabolized by tubular cells, could be used in athletes, while it is virtually independent from body mass.