Last year i changed from working retail to an outside field tech job, it involves no or little physical labor, recently i had to do one day on a dirt site outside and the next day in the desert at 113 degrees. i drank 11 bottles of 16oz h2o but still ended up in the er. so far it seems after reading the other comments, that though the lisinopril does lower my bp, it also causes depletion of electrolytes in high heat areas if you are not acclimated to it. I also now know why i have constant throat problems, coughing and clearing of my throat after meals, and my muscle fatigue...