I'm really confused how maligant hyperthermia can be triggered through excersie or hott environments? i thought it happened only under gen anesthesia

You are correct.: Severe hyperthermia may be caused by heat stroke ( inability to dissipate a large environmental heat load), neuroleptic malignant syndrome ( a reaction to medications) and malignant hyperthermia ( a rare inherited disorder triggered by exposure to anesthesetic agents).

Typically: Malignant hyperthermia is typically an episode which can occur under the triggers of certain anesthetic drugs while under a general anesthetic. There are reports of environmental stresses causing a trigger also. Important think with mh is know you have it and eliminate stresses or drugs that cause trigger. Mh is a very severe medical condition requiring immediate intervention.