Heatstroke can reprogram your DNA, putting survivors at risk of developing future health problems in the years that follow.

Untreated, this medical emergency can result in permanent disability or death. Someone suffering from heatstroke—defined as a core temperature of 104 degrees Fahrenheit but sometimes as high as 106 degrees Fahrenheit—may appear confused and require immediate cooling, ideally with an ice bath.

Since the condition involves losing the ability to cool oneself, clinicians sometimes see someone who has exertional heatstroke—like a high school athlete who is really sweaty—and don't realize the heat-related illness has already progressed to heatstroke. Classic heatstroke typically occurs among the very young or the elderly.

Warning signs that the body is overheating include rapid breathing, cramps, heavy sweating, nausea, and feeling lightheaded. Drinking plenty of fluids, seeking shade, and cooling the body down as quickly as possible with icepacks can help reduce the risk of heatstroke.

One often-cited average estimate of annual American heat deaths—roughly 1,200 per year—is based on death certificate data, but it may be a significant undercount because heat kills through cardiovascular, kidney, and respiratory causes that are more likely to be cited on those documents. (Separate analysis that looked at data from 1999 to 2023 found that the highest number, in 2023, was 2325.)

Heatstroke, true to its name, looks more like a stroke. Its symptoms include severe disorientation, irritability, and seizures, among others. A patient does not need to have collapsed in order to have exertional heatstroke, but if someone is talking clearly, they likely have heat exhaustion, and it hasn't progressed to heatstroke.

Evidence shows that people with schizophrenia have an inherently harder time regulating internal body temperatures. They may also struggle to find safe shelter during extreme heat, and their prescribed antipsychotic medications often have dehydrating effects, collectively elevating the risk of heat-related illness and death, as illustrated by this article that focuses on the final days of Stephan Goodwin's life in 2022.

Dog bites increase in summer, birds struggle to learn, and goats pick more fights. Scientists are unraveling new details about how heat impairs animals' neurological systems.

Drugs that narrow blood vessels, beta blockers that regulate blood pressure, diuretics, antidepressants, and antipsychotics can all affect the body's ability to regulate its internal body temperature, and so individuals taking these medications need to take special care in extreme heat and when exercising in hot conditions.

Stress is a normal part of everyday life, and it’s not necessarily all bad. But chronic stress—the kind that leads to burnout—can change the size and functioning of parts of your brain. It can alter the ability to make new brain cells and memories and even potentially modify your DNA.

America is generally experiencing more frequent extreme heat days, over a longer period, in certain parts of the country. The heat-related death toll is rising, and beyond those direct deaths, extreme heat can also have troubling ripple effects including elevated violence and decreased productivity.

In the lab, mice dosed with probiotics prior to inducing exertional heatstroke, had better cognitive outcomes. This evidence underscores the links between the gut microbiome and the brain, at least in rodents.

Protocols for the standard treatment recommendation for heatstroke—whole-body cold water immersion—were built based on studies almost entirely in men. The research wasn't replicated in women, who typically cool faster than men during cold water immersion, raising questions about standard protocol safety for women, due to the risk of overcooling.

Between 2000 and 2009 one study suggests annual heat deaths averaged around 2,670, but between 2010 and 2020 that figure was likely more than 4,000. Researchers studied 54 million death records from the contiguous US and created mathematical models to arrive at these figures, noting that a combination of aging populations and climate change drove that increase.

Analysis of more than 130,000 runners in Tel Aviv events during a seven-year period indicated that the runners were 10 times more likely to experience heatstroke than serious cardiac problems. Scientists suggest that runners should take 10 to 14 days to acclimate to a hot climate before tackling a serious run.

The damage can increase the risks of cancer, cataracts, heart disease, and other illnesses based on exposure times and intensities. Contaminated food, water, air, or soil from near nuclear accidents can further prolong one's exposure.

Many of those deaths were from football specifically, where student athletes play in hot conditions while wearing heavy protective gear. Few states mandate heat guidelines for school athletes, and this article says that's of increasing concern with more high heat index days.

This hereditary blood disorder affects the shape and function of red blood cells. A US military study found that among recruits the incidence rate of exertional heat-related illness was 48% higher among those who had sickle cell trait as compared to those without. Easing into intense exercise and gradually increasing exertional frequency and intensity is recommended.

Although often considered indestructible, scientists observed these creatures could endure temperatures near 150°C for only a few minutes in their tun state. Outside this state, only half the samples in a Danish study survived 37.1 degrees Celsius (98 degrees Fahrenheit) for 24 hours, making tardigrades extremotolerant rather than extremophiles.

Eric Klinenberg wrote a book diving into the specifics of the heat wave. His book, detailing the stories and context fueling more than 700 deaths during just one summer week, helps readers understand how social infrastructure lapses, power outages, and ineffective heat responses led to so many deaths.

It's essential to remain hydrated in summer weather to keep your body healthy, but one reason is to help dilute minerals that naturally build up if they aren't excreted in our water-fueled urine. Doctors recommend people generally drink 64 ounces of water a day and also eat foods with salt to help ward off dehydration.

In the case of radiation-induced distortions in a DNA strand, specialized proteins can cut out entire segments and rebuild them using the second strand as a complementary template. If both DNA strands are completely severed, proteins interlace undamaged DNA with the severed DNA and rebuild both using complementary base pairing.

Genetic mutations occur when cells replicate, which requires a copy of DNA to be created, and involve substituting, deleting, or inserting letters in a cell's genetic code. Mutations can be caused by normal cellular processes, chemical exposure (e.g., carcinogens), or radiation and may result in genetic disorders or genetic variations that drive evolution.

Large doses of ionizing radiation can damage the body within minutes, particularly in the bone marrow and inner layer of the digestive tract. Victims may briefly seem fine before rapidly deteriorating as immune failure, infection and organ collapse set in.

Burnout isn't just a feeling—it physically affects the brain. Prolonged stress impairs regions of the brain responsible for decision-making, emotional control, memory, and more. It can also lead to chemical imbalances, like reduced dopamine and norepinephrine levels, that worsen these effects.

This Radiolab podcast episode takes on the idea that though our human bodies are too warm for the majority of fungal species to effectively replicate inside our bodies, that's not the case for reptiles. Yet when those species warm their bodies by basking in the sun on rocks, they can soak up heat and may also help keep fungal infections in check.

Research published in 2024 suggests that with more severe heatwaves and natural disasters, scientists expect there to be a rise in foodborne disease, especially in Africa and Asia. Already, there are an estimated 600 million food poisoning cases and 420,000 deaths annually. Diarrhea is the most common cause of those deaths.

The human brain handles stress and emotional traumas similarly. In response to the emotional stress of a situation like the death of a loved one, divorce, or abuse, the brain may strengthen or weaken connections between nerves to form new neural connections. Over time, chronic stress can diminish brainpower, reducing overall nerve growth and memory to shift resources to enable elevated fear responses and enable humans to survive.

In response, the NFL overhauled its heat approach and no other player has since died from heat-related illness. Even at the high school level, research suggests safety measures should include: mandating water breaks, keeping a cool tub available, and having athletes acclimate to high-temperature playing conditions for a week or longer before donning the full set of protective equipment.

Floods are a distant second, followed by hurricanes. That's according to data reported by the National Oceanic and Atmospheric Administration.

Instead of deleting genes, epigenetic editing modulates their activity. A new paper tests if it’s able to undo a genetic effect of early alcohol exposure.

Over time, this cellular defense system can inadvertently damage cells and tissues when it's in this heightened alarm mode over a prolonged period. This occurs because, when immune cells are sent somewhere without a true target, they may attack healthy cells and tissues.

Stress is our body’s internal mechanism to deal with changes in our internal balance. As such, the stress response affects nearly every organ system through a cascade of both fast and slow hormonal changes. While short-term stress can be adaptive, long-term stress may cause serious health issues.

Examining the cellular structure of the plant under heat, scientists observed the formation of novel, cup-shaped chloroplasts and mitochondrial relocation, which shifted the plant's optimal photosynthesis temperature to 45 degrees Celsius (113 degrees Fahrenheit) as it tripled in mass over 10 days. Engineering these mechanisms in crops may help optimize them for hotter environments.

Prolonged inactivity, like sitting for long periods, slows metabolism, weakens muscles and bones, and impairs insulin function. When these negative changes persist over time, the cumulative result is an increased risk of cardiovascular disease, diabetes, and many cancers.

While outward signs of aging, like gray hair and wrinkles, are easy to spot, aging changes at the cellular level are less obvious. The decline within cells stems from numerous sources, including DNA damage, oxidative stress, and accumulated waste.

We're not sure yet. Researchers at the University of California San Francisco are studying why some conditions and behaviors, such as low-oxygen environments and exercise, benefit the aging process, hoping to reveal potential health applications. Some of this research focuses on klotho, a naturally occurring age-regulating hormone named after the Greek Fate Clotho. Animal studies on klotho brain injections found subjects had improved memory recall and age-related degeneration resistance.

A study examining the muscle function of older adults who have at least one adverse childhood experience (ACE) suggests that trauma digs itself into muscle cells. Participants who reported childhood trauma were found to have lower maximum levels of cellular energy than people who reported fewer or no ACEs. Such compromised mitochondrial function "doesn't bode well," as it relates to a variety of health and age-related outcomes.

The world is seeing regular heat waves with multiple causes, including so-called "heat domes," a term rising in use in recent years. A heat dome occurs when the atmosphere traps hot ocean air like a lid or cap, creating stifling conditions and resulting in extended periods of heat. See an illustration of this phenomenon and read how it works with this brief explainer.

Stress is a normal human response that has evolved over millions of years to handle changes or threats in our environment. This article is a helpful overview of the biological basics of this response. While it is not harmful to our physiology in the acute setting, chronic stress can lead to damaging changes in the human body over many years.