Of all extreme weather conditions, heat is the deadliest, NPR health correspondent Maria Godoy reported on June 13. The human body has a natural cooling system — sweating — but that system can manage only so much when temperatures and humidity climb.
When the body can no longer shed heat fast enough, core temperature rises. At a certain threshold, heatstroke sets in. If the body’s internal temperature climbs high enough, proteins in cells begin to break down and vital organs start to shut down. That is one of the three main pathways by which heat can kill, Godoy reported.
A second pathway involves the cardiovascular system. To cool itself, the body sends more blood to the skin. That forces the heart to work harder, pumping blood away from internal organs. For people with preexisting heart conditions, the increased strain can lead to cardiovascular collapse.
The third pathway operates when organs begin to fail under the heat. When the kidneys or liver stop functioning properly, toxic substances can accumulate in the blood, setting off a cascade of systemic failure.
To stay safe, public health experts recommend remaining in air-conditioned spaces, drinking water frequently, limiting outdoor activity during the hottest parts of the day, and checking on vulnerable individuals such as older adults and those with chronic medical conditions. Early signs of heat-related illness include heavy sweating, weakness, dizziness, nausea, and headaches.
MSI previously reported that unusual April heat waves threatened temperature records across the U.S. earlier this year, and that extreme heat events have become more common and more intense as the climate warms. Read MSI’s earlier coverage of the April heat wave.