When the urine becomes dark and thick, the metabolism of the body becomes obviously faster, and the metabolites increase accordingly. A large number of metabolites such as urobilin and urocholic acid are excreted with urine. These things are all colored. If you excrete too much, the urine will turn yellow. In addition, during strenuous exercise, you sweat more, lose more water in your body, and reduce the urine volume accordingly, so that the urine is concentrated and the color of urine becomes darker. This phenomenon is physiological. As long as you have a proper rest and drink more boiled water, the color of urine will fade.

So don't worry!