42 Hyper thermia Whe n heat pr oduction e x ceeds heat loss within the body h yper thermia ma y de v elop The f our main types of h yper thermia or heat stress are 1 Heat cram ps 2 Heat syncope f ainting 3 Heat e xhaustion 4 Heat str ok e Heat cram ps and heat e xhaustion result fr om deh ydration and salt deple tion as the body sw eats t o lo w er its int ernal t em perature Heat str ok e occur s when the core body t em perature e x ceeds 4 1C 1 05F and the body cooling mechanisms ha v e f ailed Hyper thermia can de v elop during e x er cise in only mod erat e t o ho t t em peratures eg 30C or 86F with f airly high humidity 50 or more Pre v ention Ri sks of h yper thermia are increased b y rising air t em perature and humidity le v el b y solar and refect ed radiation b y clo thing that doesnt allo w good v entilation close t o the skin sur f ace b y lo w ftness le v el but no t e x em pting e v en the best athle t es when the yre com pe ting in e xtreme conditions and b y large body build the less bulk be it muscle or f at the more effcient the bodys cooling syst em R ecent illness and lack of heat acclimatization increase the risk of h yper thermia Ex cessiv e e x er tion is of t en the precipitating cause of body core o v er heating