CINCINNATI (WKRC) - As temperatures climb into the upper 90s and the heat index pushes well above 100 degrees, doctors are urging people to take the extreme heat seriously. Heat-related illnesses can develop quickly, especially for older adults, young children, people who work outside, and those with underlying medical conditions. Dr. Konstantin S. German, a cardiologist with TriHealth, said dehydration is one of the biggest concerns during extreme heat.