Creatinine will be mildly elevated after exercise. Creatinine is an indicator of kidney function, and creatinine is a product of muscle metabolism, if muscle metabolism is enhanced, the creatinine produced will naturally increase, and exercise will enhance muscle metabolism, therefore, creatinine will be mildly elevated after exercise. If you eat more lean meat, which is equivalent to consuming more exogenous creatinine, it will also lead to a mild increase in creatinine. Therefore, if you suspect that your kidney function is abnormal, you should avoid strenuous exercise the day before or on the day of the kidney function test, and eat less or no lean meat, so that the test results can be more accurate. If the patient’s kidney function is normal, this mild increase will not exceed the upper limit of the normal value of creatinine, which is 110 μmol/L. If the patient’s kidney function is abnormal and he already has kidney failure, the creatinine will increase more obviously after exercise or eating lean meat.