There are 27 ways a heat wave can kill you, according to a report in the American Heart Association journal Circulation: Cardiovascular Quality and Outcomes (November 2017). By 2100, at the current rate of greenhouse-gas emissions, three-quarters of the world's population could be exposed to deadly heat conditions every year, according to the report. The researchers said that it is not just the old, sick, and those suffering from cardiovascular disease who are at risk, although they are more vulnerable. Anyone who experiences elevated body temperature during a heat wave is at risk. See also: Extreme weather events; Global warming; Greenhouse effect
Scouring online databases for the physiological pathways of deadly heat, the researchers identified five physiological mechanisms—ischemia (decreased blood flow), heat cytotoxicity, inflammatory response, disseminated intravascular coagulation (blood clotting), and rhabdomyolysis (skeletal muscle breakdown)—and seven vital organs—brain, heart, intestines, kidneys, liver, lungs, and pancreas—that could be critically affected. Of the 35 possible combinations, they found medical evidence for 27 ways that physiological mechanisms could cause heat-related organ failure and death. For example, in extreme heat, all five physiological mechanisms can affect the liver and kidneys, while all seven organs are affected by the inflammatory response. See also: Blood; Brain; Circulation disorders; Heart (vertebrate); Inflammation; Intestine; Kidney; Liver; Lung; Muscular system disorders; Pancreas
During a heat wave, the best advice is to limit heat exposure during the hottest hours of the day and to stay hydrated. In a warming world, air conditioning is one of the few options for limiting heat exposure, for those who can afford it. But as the researchers pointed out, air conditioning will be of little help during a power outage. See also: Air conditioning
