Heat-related deaths have risen nearly seventeen percent each year for the last decade and older adults are known to be at greater risk. Other chronic conditions of the elderly are also exacerbated by heat, including heart disease, kidney disease and diabetes. They may also take medications that interfere with their body’s heat regulation. How hot does it have to get before heat-related visits to hospitals? NYU researchers tracked emergency department activity during heat waves. They found heat indexes over ninety were likely to cause a jump in ED visits. The study offers guidance to communities that start their heat warnings and cooling centers at higher feel-like temperatures. The study appears in JAMA Network Open.