The Severe Effects of Extreme Heat on the Body and Mind
High temperatures are here to stay, and their extreme impact is evident in heat waves across Israel and Europe. Beyond the danger of dehydration, how does extreme heat affect our physical and mental health, and what risks should we watch for?
Heat waves demonstrate in a harsh way that the impact of high temperatures is not limited to sweating and general discomfort, but can be fatal. What happens to the body when it overheats?
When the air temperature exceeds skin temperature (usually around 36°C) or sweat fails to evaporate, we begin to accumulate heat. The core temperature of our body—the temperature of our deep tissues—begins to rise. If this increase continues unchecked, it can lead to severe heat-related illnesses.
High-Risk Groups
While everyone is sensitive to heat, some are at much higher risk. Infants and children are particularly vulnerable, partly due to faster fluid loss. Certain medications also increase vulnerability: some antidepressants and antipsychotics can affect sweat production, while heart medications like ACE inhibitors can cause dehydration and strain the kidneys. Older adults, especially those with conditions like diabetes, are also at higher risk as their bodies react differently to heat than those of younger people.
The Dangers of Heat Stroke
Heat stroke occurs when the core body temperature reaches at least 40°C (104°F), potentially leading to organ failure, brain damage, and death. A major danger of heat stroke is cognitive impairment; patients often become disoriented, unaware of their surroundings, and may lose consciousness. If the body temperature continues to rise, the outcome can be fatal.
Impact on Mental Health
High temperatures can have profound effects on mental health. A 2018 study published in Nature Climate Change found that for every 1°C increase in average monthly temperature in the USA, suicide mortality rates rose by 0.7%. Furthermore, a 2022 study in JAMA Psychiatry, tracking 3.5 million emergency department visits, found that higher temperatures during the hot season increased the risk of visits for all mental health conditions, including substance use disorders, anxiety, and schizophrenia.
Harm to the Heart and Kidneys
Extreme heat is particularly dangerous for those with pre-existing conditions, from type 2 diabetes to COPD. Cardiovascular strain is a major concern, as heat can trigger heart attacks. Approximately one-quarter of heat-related deaths are caused by a combination of heat stress and cardiovascular disease.
Dehydration also poses a significant threat to the kidneys. As the body heats up, blood flow is diverted from internal organs to the skin, and the kidneys reduce urine output. Over time, chronic dehydration can lead to kidney failure.
