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

Exertional heatstroke is a top killer of athletes and soldiers-in-training

Often characterized by collapsing while exercising in the heat with intense sweating, this type of heatstroke among otherwise healthy people occurs when the body loses the ability to cool itself during intense exercise and the body's core temperature has risen to 104 degrees Fahrenheit or higher and cannot cool itself. If treated quickly, it's often survivable, though it can cause lasting damage.

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.

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.

How the gut microbiome can affect heatstroke risk

Some research suggests that our gut microbiome influences our risk of exertional heatstroke. If exercise boosts our body temperatures to unsafe levels, increasing gut permeability, that can cause a "leaky" gut—allowing bacteria and other gut microbes to leak into the bloodstream and potentially trigger endotoxemia, a potentially life-threatening inflammatory response that can occur with heat exhaustion and heatstroke.

Sickle cell trait can put people at elevated risk of heat-related illness

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.

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.

How endurance athletes can build resilience

Long-distance runners and other endurance athletes can improve their performances using tips explored in this article. Findings from two recent studies show that strength training, high-altitude training, and intense interval sessions are all potential methods for ameliorating long-term athletic capabilities.

Runners typically burn 2,600 calories during a marathon

They also burn between 5-10 pounds of water weight, often feel more focused and elated (thanks to increased neurotransmitters), and, oddly enough, temporarily grow about a half-inch shorter due to back muscles tensing.

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.

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.

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.

Research suggests AI data centers may be creating microclimate heat islands

An analysis of satellite data from 2004 to 2024 showed that land surface temperatures in the areas surrounding AI data centers typically increase by an average of 2 degrees Celsius (3.6 degrees Fahrenheit) after they begin running. Across the 6,000 global data centers analyzed by the study, temperatures increased by as much as 9.1 degrees Celsius (16.4 degrees Fahrenheit).

Ranking the 10 hottest places on Earth

Death Valley in California often gets the press for the hottest recorded air temperature in the world. What about the runners-up? This list compiles the rest of the Earth's hottest spots, from Jeddah in Saudi Arabia to Kebili in Tunisia.

The marathon is only getting more popular

The marathon has become a part of popular culture, with races in nearly every major city. The largest is the New York City Marathon, which started in 1970. Over 55,000 runners participated in the 2024 race. Its popularity doesn’t appear to be slowing, with younger generations increasingly lacing up their shoes for the race of a lifetime.

Civilians on short-term spaceflights can experience long-term astronaut health impacts

A collection of 44 studies—primarily based on data from a 2021 tourist trip to low Earth orbit—identified immune system disruption and some kidney damage in tourists, with women appearing to recover from space travel faster than men. Return trips from Mars may require human travelers to be on dialysis.

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.

Daylight Saving Time is linked to a rise in heart attacks and strokes

Losing an hour of sleep with seasonal time changes is not good for our health and it’s linked to risks for the first couple days of Daylight Saving Time, including a short-term rise in heart attacks and strokes. Scientists theorize these elevated risks are linked to the disruption to the body’s circadian rhythm.

Swimming boosts the risk of contracting swimmer's ear by fivefold

The term swimmer's ear is a bit of a misnomer since other factors including scratches to your ear from Q tips, trapped perspiration inside the ear when you sweat, and living in tropical climates can elevate the risk of contracting this outer ear infection. But swimming poses the greatest risk: widely cited research has found that swimming elevates the risk of contracting this infection fivefold.

Certain vaccinations may be more effective when given around the middle of the day

A 2023 analysis of the health records of more than 1.5 million people in Israel suggests that COVID-19 vaccines may be more effective when received around the middle of the day. Separate early research also suggests there may be similar trends for influenza vaccines.

Health officials recommend at least 150 minutes of aerobic exercise per week

This official guideline from the CDC defines the baseline recommendation for healthy adult activity. These recommendations also emphasize that any movement is better than no movement, and that even short bursts of activity spread throughout the week benefit the mind and body.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

Review the health effects of living near oil refineries, including increased respiratory risks

An analysis of 54 studies published between 1977 and 2024 in 15 international regions found evidence that proximity to refineries increased the risks of leukemia, asthma, bronchitis, and respiratory symptoms. Several studies also identified worse cardiovascular function in children and adults living near refineries, alongside other acute and chronic health impacts.

Feels-like temperature indicates how our skin will feel

When the wind is moving faster, we tend to feel colder due to the so-called "wind chill," which cools our bodies by moving heat away from them and making water evaporate faster. On the other hand, high levels of humidity can make us feel 10 degrees warmer at times.

Over time, people develop a resistance to spicy foods

TRPV1 is a receptor in the body that detects potentially harmful things and responds in a variety of ways, including sweating, tearing up or a runny nose. Over time, more exposure to spicy foods can build up a resistance that minimizes these reactions.

Black mold isn’t more worrisome than other colors of mold

Black mold typically refers to Stachybotrys chartarum, a mold that commonly appears in damp or water-damaged areas of the home. Black mold—and other molds—won’t typically make otherwise healthy people ill, and all molds should be treated the same with respect to health risks and removal. If you have mold allergies, mold can cause an allergic response, and it can trigger asthma attacks for people with asthma. If you have a compromised immune system, then black mold exposure can also cause a fungal infection in your airways or elsewhere in the body.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak annually

If someone is exposed to one of these plants for the first time, it can take several weeks to develop a rash.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

Firework or sparkler burns, even if they cover a relatively small area of skin, can significantly affect our range of motion.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

Radioactive elements can introduce software errors because the ionizing radiation they produce can detach electrons from atoms, and computer code relies on the distribution of electrons.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

The deadliest aspect of volcanic eruptions is often not lava, but pyroclastic flows—avalanches of ash, gas, and rock that can move more than half the speed of sound.

Double world record holder Hunter Ewen helped conquer his fear of balloons, called globophobia, by training to win Guinness World Record titles for balloon inflation.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

Telehealth demand for GLP-1s for weight loss is booming as consumers seek easier access.

Alzheimer's can lead to brain shrinkage, with an average of around 2% of volume reduction per year

Stanford built a Google Maps for the Roman Empire, revealing how much it cost to travel in the ancient world

Electrical grids worldwide must double their power delivery capacity by 2050 to meet surging demand from AI and electric vehicles.

View the ten deadliest tornadoes in US history.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

American dance legend Martha Graham, sometimes called 'the Picasso of dance,' refused to perform at the 1936 Olympics in Berlin and conceived the piece 'Chronicle' in response to the experience.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

The US first hosted the World Cup in 1994, a tournament that lives in soccer infamy for its poor planning and the murder of Colombian player Andres Escobar, who'd accidentally scored on his own net.

Take a 3D tour of the Hajj, Islam's annual pilgrimage to Mecca, undertaken by over 1.5 million Muslims.

Tattoos remain visible on your skin thanks to immune cells called macrophages

In 1939, baseball star Lou Gehrig delivered his inspirational 'Luckiest Man' speech after retiring due to the health condition that now bears his name.