Extreme heat puts people at risk of developing kidney stones

Heatstroke is when the body's core temperature becomes dangerously high—and needs to cool

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.

Heatstroke—from overexertion or extreme heat—drives core body temperature to 104 degrees Fahrenheit or higher, setting off a cascade of problems in the body.

13 unconventional ways to stay cool during heat waves

While air conditioning is the default solution for many in a heat wave, it can get expensive while requiring the consumption of fossil fuel energy. So, how else can you stay cool during a heat wave? This list compiles some practical, at times quirky, suggestions, including an ice-pack-filled aubergine hat.

Heatstroke occurs when the body reaches 104°F or higher and can't cool itself

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.

Certain medications that affect blood flow or mood boost the risk of heatstroke

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.

It is recommended that humans consume 2.0 to 3.7 liters (about 4.2 to 7.8 pint glasses) of water daily to replace water lost through breathing, sweating, urination, and bowel movements.

Exertional heatstroke is a leading cause of death among athletes and soldiers in training, and typically occurs when someone sweats intensely while exercising in the heat.

Health workers may cool body temperatures with convection cooling

That's spraying a patient with water and putting fans over them. Cooling the body by removing clothing and placing cold water and ice packs—and not blocking evaporation—are essential cooling steps.

Heatstroke is sometimes missed because the patient is really sweaty

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. (Some users may encounter a paywall.)

Heatstroke can reprogram your DNA, putting survivors at risk of future health problems.

More extreme heat days are putting human health at risk in both the short and long term

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.

Some research suggests that the gut microbiome influences our risk of heatstroke, with elevated exercise levels raising body temperature to unsafe levels and increasing gut permeability—causing a "leaky" gut.

Heatstroke treatment guidelines were built almost exclusively on research in men

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.

Heatstroke deaths may be massively undercounted—perhaps by a factor of 10

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.)

Our bodies cool us down by sweating because water requires a significant amount of energy to change state from liquid to gas, making it an ideal medium for carrying thermal energy away from our bodies.

Extreme heat is neurologically impairing animals

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.

67 US high school athletes died from exertional heatstroke between 1982 and 2022

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.

Extreme weather conditions heighten cholera risks in settings like refugee camps

Runoff from sewage—exacerbated by situations like flooding or extreme rains—heightens this threat. Increasing temperatures also create the ideal conditions for the bacteria to reproduce, increasing transmission risks.

Although consuming saltwater can dehydrate and kill organisms, some fish survive by using specialized gills that leach excess salt from their bodies back into the surrounding water.

Cold-blooded reptiles seek heat, and that behavior may help combat fungal infections

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.

Heat-related complications are of greater concern for distance runners than cardiac threats

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.

City structures cause localized heat zones hotter than nearby rural areas

Urban materials like asphalt and concrete trap heat, while cities lack cooling features like trees and water. Due to hot runoff, urban streams can heat up by as much as 18°F more than forested streams.

Yes, you can take too many vitamins and they can make you sick

Too much of vitamins A, D, E, and K (which are fat-soluble) can build up in the body and cause serious health problems, including liver damage, kidney stones, and blood clotting irregularities. Excess iron and calcium can also make it harder for the body to absorb other needed nutrients.

Heat-related deaths may have climbed by more than 50% over 20 years

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.

Eating too much salt can worsen vertigo

High salt intake can cause fluid retention in the inner ear, worsening vertigo. Slashing sodium amounts (and caffeine and alcohol consumption) are particularly recommended for those suffering from Ménière's disease to help stabilize inner ear fluid levels.

Vitamin D supplement pills are linked to rising cases of vitamin D toxicity in the US

Vitamin D deficiency is common. But taking Vitamin D supplements in doses exceeding 4,000 IU/day (a measurement of vitamin biological activity) for prolonged periods can raise bodily concentrations of this vitamin to dangerous values. US National Poison Data indicates that the annual average of vitamin D poisonings from 2000-05 was 196, but this rose by 1,600% to 4,535 per year for the period of 2005-11.

Oral rehydration solution was developed in the 1960s in response to cholera deaths.

Heat exhaustion is the most likely diagnosis if someone is talking clearly

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.

How the body produces urine

Things seem so simple when nature calls. But, how does the body actually produce the urine we so regularly and thoughtlessly expel? This detailed, comprehensive animation walks viewers through every step with precise illustrations, from the kidney's filters (known as nephrons) to the direct nerve connecting the bladder to the brain. See how the body does it here.

Reduced inflammation from cold plunges lacks scientific support

The cold water triggers immediate cold shock, increasing heart rate and blood pressure, and prolonged exposure can lead to cold-water incapacitation and hypothermia. Plungers are encouraged to enter the water slowly and manage their breathing to reduce the risk of shock. Warm baths post-plunge are discouraged, and exercise is generally better for recovery.

A look at the concentrations of water in the human body and various organs

When we're born, about three-quarters of our bodies are composed of water, dropping to an average of 55-60% for the average adult. The lungs are over 80% water, the kidneys and spleen about 80%, and the heart and brain are approximately three-quarters composed of water—about the same moisture as a banana.

Schizophrenia increases heat death risks in several complex ways

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. (Some users may encounter a paywall.)

Korey Stringer, of the Minnesota Vikings, died of heat-related illness in 2001

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.

We can get food poisoning from spending time in swimming pools, lakes, rivers, and ponds

Some of the same pathogens that may sicken us in food or water may also sicken us in recreational swimming environments. Bacteria can rub off of people’s (or animal’s) bodies or contaminate the water through a diarrheal episode. Washing your hands for at least 20 seconds before eating food if you are at the beach, pool, or other similar environments and being sure not to swallow the water are ways to help keep safe.

Hundreds of vulnerable Chicago residents died in 1995 during a long-lasting heat wave

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.

Unlike America's recommendations, Australian authorities don't encourage routine sunscreen use for darker skin tones—reasoning that melanoma risk is low, and it's better to get UV exposure to help the body naturally produce vitamin D.

Children are at increased risk of contracting swimmer's ear

Kids may be more likely to spend time at the pool so they have that water exposure. They also tend to have narrow ear canals, a prime location for water to get trapped. Frequently wearing earbuds or excessively trying to rid ears of earwax, however, can also increase the chances of painful swimmer's ear infections at any age.

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

10 percent of SAD cases occur in the summer

Despite its significantly lower incidence, summer-risk SAD is as significant as its winter counterpart. Rather than being prompted by less light, the summer version is typically spurred by high temperatures, strong light, distinct summer time social pressures (appearing in a bathing suit, for example), and pollen. Common treatments include keeping cool and prioritizing sleep.

Mineral and chemical sunscreens protect differently, but both guard against UV damage.

Cold water swimming can induce positive stress

The tradition of cold water swimming (or taking a cold plunge, or even a cold shower) has been shown to release the same hormones triggered during a stress response. This can have the effect of increasing blood flow, improved mental acuity, and more.

Demystifying sunscreen

Sunscreen is helpful all year round. Experts argue a minimum level of protection is SPF 30. There are two kinds of sunscreen: mineral (a physical barrier) and chemical (absorbs UV light). No new sunscreen ingredients have been approved in the US in decades, so foreign products are common.

Gladiators followed a mostly vegetarian, high-calcium diet

Analysis of skeletons from a gladiator cemetery at Ephesus by researchers at the Medical University of Vienna found little meat consumption but unusually high calcium levels—likely from drinking wood ash mixed with water to promote weight gain and protect vital organs.

How often should you clean your water bottle?

Experts say a daily wash of a high-use bottle is key to keep away unwanted bacteria and odors. For a good clean, use water—as hot as 140 degrees Fahrenheit—mixed with soap, swirling the mixture in the bottle before letting it sit for 20 minutes. Learn more tips with this quick overview.

EXTREMA is a smart city system protecting residents from heat-related health risks

The mobile application is designed to protect citizens in select European cities from extreme temperatures by calculating the heat index at a specific location and providing personalized information to users. Municipal governments can also utilize it to inform emergency responses, such as determining when and where to open cooling centers.

The halting of human bone growth helps manage heat produced from metabolism

While fish, amphibians and reptiles get bigger throughout their lives until they die, their slower metabolisms allow their bodies to regulate the resulting smaller temperature increases. In humans, hormones triggered during puberty harden growth plates, ending bone lengthening.

1 in 4 people around the world don't have access to clean water

Poor water sanitation puts people at risk of acquiring this diarrheal infection. Cholera infections are on the rise due to extreme weather events and conflict. In recent years there have been cholera outbreaks in locations that hadn't seen the disease in many years, including Haiti.

How to survive hypothermia

Hypothermia is a deadly risk for those living in cold areas, causing around 1,500 deaths a year in the United States. Stay safe with tips from this article, which cites research papers to help prevent and treat the condition. Take note of the best fabric to wear when cold weather hits—not cotton but wool.

Legionnaires' disease is a serious lung infection caused by Legionella bacteria, and it's often contracted from inhaling contaminated mist or water.

Listen to why extensive ear rinsing can create problems

The clinician who hosts this podcast discusses how his patient developed swimmer's ear after he flooded his ears with water during his daily showers, ostensibly to clean them. The resulting itchy, painful ears were the result of removing protective earwax in the ear and also altering the typical pH of the ear.