A 62-year-old man collapsed after a routine morning walk between 8 am and 9 am. Being hypertensive, diabetic and having a stent in his heart, he was always cautious about stepping out in midday heat. Still, he felt dizzy, weak and sweated profusely when he entered the OPD of Dr Rommel Tickoo, Director, Internal Medicine, Max Healthcare, Delhi. “Then his sweating reduced, a dangerous transition indicating failure of the body’s cooling mechanism. Nausea followed, he could neither eat or drink anything. He complained of mild breathlessness, gradually became disoriented and drowsy, eventually requiring assistance to walk and collapsing in a heap. His heart was under stress,” says Dr Tickoo. By the time he was evaluated, his temperature was elevated, his blood pressure had dropped and his pulse was high. His blood sugar had risen sharply to 250 mg/dL, a stress response compounded by dehydration.…