Why fever occurs in some cases after Excercise?
A slight/mild increase in temperature is normal coz of the muscles having generated heat during the straineos exercise and in a hot and humid environment (exertional heat illness), the body will correct this by sweating. Also, if engaging in an exercise routine one hasn't done before and/or requires more physical exertion. If temperature goes way and above what is considered normal, indicates a more serious condition like heat stroke.