2.1.1. Changes in sCyst-C after a Marathon

There were several studies dedicated to study changes in sCyst-C level after exercise. The increase in sCyst-C after a marathon was first noticed by Mingels et al. In this study of 70 recreational runners, the authors showed that the increase in sCyst-C is lower than the increase in sCr after exercise. This increase after a marathon was half that of creatinine (34% vs 53% increase, and after correction for the effect of dehydration, 21% vs 42%). Serum Cyst-C was increased above the upper reference limit in 46% of runners (in 26% after correction) [20]. Very similar changes—a significant increase in the sCyst-C level immediately after a marathon run—were observed by Scherr [22], McCullough [23] and Hewing [24] (Table 2).


#### **Table 2.** Changes in sCyst-C level after a marathon.

**Abbreviations:** sCyst-C—serum cystatin-C.

The main differences in these studies concerned changes in the follow-up, but the time of the follow-up was defined in different ways. Therefore, it is difficult to compare those data. Nevertheless, all studies showed a rapid decrease in sCyst-C at rest.
