"Although thoracic sympathectomy is commonly used to reduce upper limb sweating, it may also lead to facial anhidrosis and disturbed cardiovascular responses to temperature. The resultant effect on overall body heat loss has not been documented. We present a case of a young patient with previous thoracic sympathectomy who suffered severe heat stroke after heavy exercise. http://ats.ctsnetjournals.org/cgi/content/full/84/3/1025