How much does extreme heat “cost” us? A lot, in terms of human lives (just think of the massacre of pilgrims in Mecca, with over a thousand deaths), Health (increases the spread of disease-carrying insects, ticks and parasites) e poverty (health inequalities worsen). The photograph is taken from the report «The Lancet countdown: health and climate change in Europe», published on Lancet Public Health: From 2003 to 2022, heat-related mortality increased on average by 17 deaths per 100 thousand people per year in Europe and the increase was greater in women than in men.
Extreme heat in the USA
And while Italy is divided in two (storms – with damage – and cool temperatures in the North and scorching heat in the South), the United States faces an extreme heat warning for one hundred million people and the risk of huge blackouts due to the number of air conditioners in operation. Not to mention the fires. The Italian Ministry of Health has activated the “heat code” in the emergency room, i.e. a preferential path for damage due to heat, and improved home care through the Uscar (Special Regional Care Continuity Units). The public utility number is also active 1500.
More irritable and aggressive
But the consequences of heat are not limited to physical problems (for example, it increases the risk of heart attacks). Several studies have shown that high temperatures can impair our cognitive abilities, making us irritable, aggressive, impulsive and even more dull, that is, less intelligent. In 2016, a “field” study was conducted in the United States: a heat wave hit Boston (with an average of 33° for several days) and some Harvard researchers led by Jose Guillermo Cedeño Laurent had 44 students take math tests five days before the temperature increase, every day during the heat wave and two days later. Result: on the hottest days students in dorms without air conditioning performed significantly worse on the tests compared to students who slept with air conditioning.
Cognitive test scores
Several other studies conducted in the laboratory have produced results similar to those obtained by Cedeño: Cognitive test scores drop when the temperature in the room rises. Specifically, some researchers found that an increase of just four degrees led to an average 10% decline in performance on tests of memory, reaction time, and executive functions. A phenomenon that could also depend on quality of sleep, heavily influenced by the nocturnal heat.
Worse performance
R. Jisung Park, an economist at the University of Pennsylvania, examined high school test scores and found that they dropped 0.2 percent for every degree higher in temperature, from 70 degrees and above. In another study, Park found that, the more days of above-average heat during the school year, the worse students perform on tests, especially when the thermometer rises above 26 degrees. The effect is more pronounced for low-income and racial minority students, perhaps because they are less likely to have access to air conditioning.
Increases aggression
The idea that it exists a link between heat and aggression was born from a simple statistical fact: on very hot days there are more murders, assaults and episodes of domestic violence. Not only. When temperatures rise, people are more likely to feel hate (you can see it for example in the comments posted on social media) e honking while driving in traffic. An experiment conducted in 2019 showed that people playing a video game behaved more aggressively in the game if they were in a warm room compared to a cool one.
Resources diverted
Kimberly Meidenbauer, a psychologist at Washington State University, believes that the increase in “reactive” aggression may be linked toeffect of heat on cognition, in particular the decline in self-control. “The tendency to act without thinking, or not being able to stop yourself from acting in a certain way, seem to be aspects influenced by the heat,” he explained to New York Times. But how can heat impact our cognitive abilities and emotions? According to some experts, many “resources” are diverted in an attempt to keep the body at an acceptable temperature. “If blood and glucose are allocated to the parts of the brain that deal with thermoregulation, it is very plausible that there may not be enough left for some higher cognitive functions,” explains Meidenbauer.
Find solutions
A bad mood could also be a lifeline: “If you can’t cool down, your brain will make you feel even more uncomfortable, so that the search for what you need to survive becomes an all-encompassing activity,” he says. Shaun Morrison, neurologist at Oregon Health and Science University. In short, the brain would go “on strike” to ensure that the individual faces the problem and finds solutions. Which is not impossible because what matters is the body temperature (modifiable, for example through air conditioning, fans, cool showers) and not the temperature of the external environment.
Anti-mug handbook
In this regard, here is the advice from the Ministry of Health:
1) do not go out during the hottest hours: during a heat wave, avoid direct exposure to the sun between 11am and 6pm;
2) improve the home and work environment: The simplest measure is the screening of windows facing south and south-west with adjustable curtains and blinds (shutters, roller shutters). Air conditioning must be used carefully, avoiding regulating the temperature at levels that are too low compared to the outside temperature; mechanical fans should also be used with caution: when the internal temperature exceeds 32°, use is not recommended;
3) hydrate: drink lots of water and eat fresh fruit it is an essential measure to counteract the effects of heat; especially for the elderly it is necessary to drink even if you do not feel thirsty;
4) Moderate your intake of caffeinated beverages and avoid alcoholic beverages;
5) light meals: digestion increases heat production in the body;
6) dress in cotton, linen or natural fiber clothing (avoid synthetic fibres). Outdoors it is useful to wear light, light-colored hats and protect your eyes with sunglasses with UV filters;
7) ventilate the passenger compartment in the car before starting a trip; if there is a ventilation system, adjust the temperature to values approximately 5 degrees lower than the outside temperature;
8) avoid exercise during the hottest hours of the day and in any case drink plenty of liquids;
9) help those most at risk (such as the elderly and infants); check the body temperature of small children, lowering it with a lukewarm shower and when possible opening the diaper;
10) give plenty of fresh water to petsleaving it in a shaded area.
