ADH which stands for Antidiruetic Hormone is a hormone procuded by the hypothalamus in our brains and helps our kidneys save the water in the body in certain situations.
The example given in the question states that the person has not been drinking water during the three mile run, which indicates a lack of water and also the loss of water by means of sweating during the running process. These would result in a much higher level of ADH in the bloodstream due to the body trying to hold onto the liquid that remains in the body to cover for the loss and lack of water.
