Heatstroke is a serious condition that can lead to permanent disability or even death. Page ContentHouston is home to sweltering humidity and dangerously hot temperatures during the summer. Conditions of extreme heat can be hazardous and even life-threatening, which is why it is important to be aware of the most serious heat-related illness: heatstroke.“Also called sun stroke, heat stroke occurs when your body becomes overheated in a relatively short period of time and is unable to cool itself back down to normal temperatures,” says Wilber Estrada, M.D., a board-certified Internal Medicine physician at Kelsey-Seybold Clinic. Without immediate medical attention, heat stroke can be fatal.“Warning signs of heatstroke may vary but include fatigue, headache, dizziness, muscle cramps, shortness of breath, nausea and vomiting,” Dr. Estrada says. “To prevent heat stroke, it is best to avoid the outdoors during the hottest time of the day—between 2 and 5 p.m. If you must be outdoors, try to drink water every 15 to 20 minutes, wear light, loose fitting clothing and take frequent breaks in the shade to cool down.”Dr. Estrada explains how to act quickly if you see someone showing signs of a heat stroke.“Move them to a shaded area or air-conditioned environment, cool the person by moistening their skin with water, have the person drink cool water if they are able and most importantly, call 911 for emergency assistance,” Dr. Estrada says.“Left untreated, heat stroke can result in permanent disabilities or death,” concludes Dr. Estrada.