“July 3, 2023 was the hottest day – the highest average temperature for the entire earth – ever recorded. The following day, July 4th, broke that record.” “A heat dome has been hovering over the southwestern section of the United States for almost a month. El Paso, Texas recorded temperatures above 100° for 27 consecutive days.” “The streets of Las Vegas are registering 162° on digital thermometers.” These were the headlines in July, 2023.
But this is not just a North American phenomenon. Europe is experiencing its own heat dome over the southern half of that continent with humidity and temperatures like what is occurring in the US. India, used to heat and humidity, is recording increased deaths in the hundreds because of record-setting temperatures. The emergency rooms in Australian hospitals have formulated a “Blue Plan” to inform the public about the dangers of exposure to extremes of heat and humidity and a “White Plan” to be launched when the heat index tops 90 degrees.
World-wide the heat index is rising. The heat index is a measure of not how hot it is, but how hot it feels. When the humidity is very high, that is, when the air contains almost all the moisture it can at that temperature, the body cannot cool itself by sweating. The evaporation of the moisture is the primary mechanism by which the body cools itself. When the air cannot contain any more moisture and sweat cannot evaporate, the body cannot cool. The air temperature “feels” hotter than it really is. And the body temperature begins to climb.
According to the National Weather Service, even at 50% relative humidity, in heat index over 80°, with prolonged exposure or strenuous activity, one should use caution to watch for the development of heat-related disorders; at 90° and higher, extremely caution; at 103°, the risk of real danger; and at 125°, the risk of extreme danger.
Health-related dangers include heat exhaustion and heat stroke. Heat exhaustion develops when the body is beginning to lose its ability to maintain body temperature at the usual normal of 97.8°. As the temperature of the body begins to rise, the loss of water and electrolytes causes the muscles to cramp. Heavy sweating will continue as the body tries to cool itself. The skin may feel cool and wet, but may begin to get warm as blood vessels of the skin dilate to radiate out the heat.
If precautions are not taken, headache develops along with confusion and dizziness as the brain is struggling with the loss of water and electrolytes. This may be followed by nausea and vomiting. The heart beat will be rapid to increase blood flow to organs that are suffering the loss of water. The urine will be very dark and concentrated as the kidneys try to salvage every drop of water.
Without interventions, full heat stroke will develop: body temperature over 104°, hot, dry, pale skin and decreasing blood pressure as the cardiovascular system collapses, sweating stops with the collapse of the autonomic system, trouble breathing as blood flow to the lungs decreases oxygen intake, followed by fainting, seizures, and death.
If these symptoms begin to develop, move to a cool, shady place, loosen clothing, drink water or electrolyte solution slowly, and use cooling methods – apply cold cloths to areas where blood vessels come close to the surface of the skin (places where you can feel a pulse). If more serious symptoms appear: headache, confusion, etc., this is an emergency. Go to the hospital or call 911 for assistance while using cooling measures.
The best approach to heat-related dysfunctions is to prevent them. The Australians use a public education slogan: slip, slop, slap, seek, and slide.
Slip on a shirt – cover up the skin to prevent further water loss.
Slop on sun screen – to prevent sun burn and the future incidence of skin cancer.
Slap on a hat – to protect the face and the brain.
Seek – a cool, shady place
Slide on sunglasses – to prevent burning the eyes and decrease the risk of cataract
development.
In addition, avoid extreme activity and prolonged exposure during times of high heat indexes. And avoid drinking caffeinated beverages and alcoholic beverages in these extreme situations because both lead to dehydration.
The elderly and the very young are especially vulnerable to the effects of a high heat index. People generally know this and are quick to protect these people. The danger is the elderly who live alone and are unable to recognize or to prevent problems from developing. But the ones most likely to suddenly find themselves in trouble are the young and the strong who think themselves invulnerable to such problems. Despite public health education and public announcements during dangerous heat episodes, many of these healthy people suddenly find themselves in deep trouble.
High heat index shows no favorites and knows no boundaries. When the heat and the humidity are high, think carefully about outdoor activities. Play with care, work if you must, but be cautious and think carefully about hydration and frequent pauses to cool off in a shady spot.
