The severe effects of extreme heat on the body and mind

Heat waves illustrate the hard way that the impact of high temperatures goes beyond sweating and general discomfort, but also the cost of human life.

What happens to the body when it heats up?

When the air gets hotter than the temperature of our skin (usually around 36 degrees Celsius) or if sweat doesn’t evaporate, we start to accumulate heat, and our core body temperature – the temperature of our deep body tissues – starts to rise. If this rise is not reduced and continues to rise, it can lead to heat-related illnesses in some people.

People at higher risk

While everyone is susceptible to the health effects of heat, some people are at much higher risk than others. Babies and children are particularly vulnerable, partly because they lose fluids more quickly. Certain medications can also make people more vulnerable to heat. Some antidepressants and antipsychotics can affect sweat production, while heart disease drugs like ACE inhibitors can cause dehydration and affect the kidneys. Older people are more likely to have health conditions like diabetes that put them at higher risk, and their bodies react differently to heat than younger people.

The Harms of Heatstroke

Heatstroke occurs when the body reaches a core temperature of at least 104 degrees Celsius, which can lead to organ failure, brain damage and even death. One reason heatstroke is so dangerous is that it can cause cognitive impairment. Patients with heatstroke often don’t know where they are or how they got there, and eventually, they can lose consciousness, and if their body temperature continues to rise, they will eventually die.

Photo: Reuters, AP, Reuters

Extreme heat can trigger mental health crises

High temperatures can have profound effects on mental health. A study found that rising temperatures are linked to higher suicide rates; A 2018 study published in Nature Climate Change found that for every 1°C increase in average monthly temperature in the United States, suicide death rates increased by 0.7%.

Heat may also contribute to more emergency department visits for mental health crises. In a 2022 study published in JAMA Psychiatry, researchers tracked 3.5 million emergency department visits and found that higher temperatures during the hot season increased the risk of emergency department visits for every mental health condition, including substance use disorder, anxiety disorders, and schizophrenia.

High heat is harmful to the heart and kidneys

High temperatures can be more dangerous for people with a range of existing health conditions—from type 2 diabetes to COPD (chronic obstructive pulmonary disease)—than for the general population. Cardiovascular problems are especially dangerous: High temperatures can strain the heart and lead to heart attacks, and put People with heart problems. About a quarter of heat-related deaths are caused by a combination of heat and cardiovascular disease.

Dehydration can also lead to kidney problems. As the body heats up, the kidneys reduce their urine output as blood flow decreases away from the internal organs to the skin and body fluid is excreted as sweat. Over time, chronic dehydration can lead to kidney failure.