Health

When heat waves turns deadly: How extreme temperatures affect the human body

Published

1 year ago

June 22, 2024

When heat waves turns deadly: How extreme temperatures affect the human body

As temperatures and humidity soar outside, what’s happening inside the human body can become a life-or-death battle decided by just a few degrees.

The critical danger point outdoors for illness and death from relentless heat is several degrees lower than experts once thought, say researchers who put people in hot boxes to see what happens to them.

With much of the United States, Mexico, India and the Middle East suffering through blistering heat waves, worsened by climate change, several doctors, physiologists and other experts explained to The Associated Press what happens to the human body in such heat.

HEAT WAVE LEAVES AT LEAST 125 DEAD IN MEXICO

Heat waves can raise your body temperature

The body’s resting core temperature is typically about 98.6 degrees Fahrenheit.

That’s only 7 degrees away from catastrophe in the form of heatstroke, said Ollie Jay, a professor of heat and health at the University of Sydney in Australia, where he runs the thermoergonomics laboratory.

Dr. Neil Gandhi, emergency medicine director at Houston Methodist Hospital, said during heat waves anyone who comes in with a fever of 102 or higher and no clear source of infection will be looked at for heat exhaustion or the more severe heatstroke.

A man pours cold water onto his head to cool off on a sweltering hot day in the Mediterranean Sea in Beirut, Lebanon, on July 16, 2023. As temperatures and humidity soar, what’s happening inside the human body can become a life-or-death battle decided by just a few degrees. (AP Photo/Hassan Ammar, File)

“We routinely will see core temperatures greater than 104, 105 degrees during some of the heat episodes,” Gandhi said. Another degree or three and such a patient is at high risk of death, he said.

How heat kills

Heat kills in three main ways, Jay said. The usual first suspect is heatstroke — critical increases in body temperature that cause organs to fail.

When inner body temperature gets too hot, the body redirects blood flow toward the skin to cool down, Jay said. But that diverts blood and oxygen away from the stomach and intestines, and can allow toxins normally confined to the gut area to leak into circulation.

“That sets off a cascade of effects,” Jay said. “Clotting around the body and multiple organ failure and, ultimately, death.”

But the bigger killer in heat is the strain on the heart, especially for people who have cardiovascular disease, Jay said.

It again starts with blood rushing to the skin to help shed core heat. That causes blood pressure to drop. The heart responds by trying to pump more blood to keep you from passing out.

“You’re asking the heart to do a lot more work than it usually has to do,” Jay said. For someone with a heart condition “it’s like running for a bus with dodgy (hamstring). Something’s going to give.”

7 WAYS TO STAY SAFE IN THIS SUMMER’S SCORCHING HEAT

The third main way is dangerous dehydration. As people sweat, they lose liquids to a point that can severely stress kidneys, Jay said.

Many people may not realize their danger, Houston’s Gandhi said.

Dehydration can progress into shock, causing organs to shut down from lack of blood, oxygen and nutrients, leading to seizures and death, said Dr. Renee Salas, a Harvard University professor of public health and an emergency room physician at Massachusetts General Hospital.

“Dehydration can be very dangerous and even deadly for everyone if it gets bad enough — but it is especially dangerous for those with medical conditions and on certain medications,” Salas said.

Dehydration also reduces blood flow and magnifies cardiac problems, Jay said.

Intense heat can ‘fry’ your brain

Heat also affects the brain. It can cause a person to have confusion, or trouble thinking, several doctors said.

“One of the first symptoms you’re getting into trouble with the heat is if you get confused,” said University of Washington public health and climate professor Kris Ebi. That’s little help as a symptom because the person suffering from the heat is unlikely to recognize it, she said. And it becomes a bigger problem as people age.

One of the classic definitions of heat stroke is a core body temperature of 104 degrees “coupled with cognitive dysfunction,” said Pennsylvania State University physiology professor W. Larry Kenney.

Heat and humidity are a dangerous duo

Some scientists use a complicated outside temperature measurement called wet bulb globe temperature, which takes into account humidity, solar radiation and wind. In the past, it was thought that a wet-bulb reading of 95 Fahrenheit was the point when the body started having trouble, said Kenney, who also runs a hot box lab and has done nearly 600 tests with volunteers.

His tests show the wet-bulb danger point is closer to 87. That’s a figure that has started to appear in the Middle East, he said.

And that’s just for young healthy people. For older people, the danger point is a wet bulb temperature of 82, he said.

“Humid heat waves kill a lot more people than dry heat waves,” Kenney said.

When Kenney tested young and old people in dry heat, young volunteers could function until 125.6 degrees, while the elderly had to stop at 109.4. With high or moderate humidity, the people could not function at nearly as high a temperature, he said.

“Humidity impacts the ability of sweat to evaporate,” Jay said.

How to cool down heat exhaustion patients

Heatstroke is an emergency, and medical workers try to cool a victim down within 30 minutes, Salas said.

The best way: Cold water immersion. Basically, “you drop them in a water bucket,” Salas said.

But those aren’t always around. So emergency rooms pump patients with cool fluids intravenously, spray them with misters, put ice packs in armpits and groins and place them on a chilling mat with cold water running inside it.

Sometimes it doesn’t work.

“We call it the silent killer because it’s not this kind of visually dramatic event,” Jay said. “It’s insidious. It’s hidden.”

Health

Scientists pinpoint why COVID vaccine may trigger heart inflammation in certain people

Published

6 hours ago

December 20, 2025

Press Room

Scientists pinpoint why COVID vaccine may trigger heart inflammation in certain people

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POST-DOSE PATTERN — New research reveals why the COVID vaccine can trigger heart issues, especially in one group

PREVENTION PAYOFF — Simple lifestyle changes could slash heart attack risk for millions

A new study has identified why mRNA COVID-19 vaccines could trigger heart issues, especially in one demographic. (iStock)

SMOKE SCREEN — A major cannabis study finds little proof for popular medical claims and flags big dangers

HIDDEN LINK — A common dental health issue may hint at a dangerous cardiovascular condition

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SCREENING DEBATE — A new study questions whether annual mammograms are necessary for most women

SUPER SPREAD — An “aggressive” new flu variant sweeps the globe as doctors warn of severe symptoms

The flu season has intensified as the new H3N2 variant causes severe illness worldwide. (iStock)

DANGEROUS DEFICIT — A nutrient deficiency has been linked to heart disease risk for millions

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CORONARY CHRISTMAS — Holiday heart attacks spike as doctors share hidden triggers and prevention tips

This article was written by Fox News staff.

Health

Aging-related joint disorder increasingly affects people under 40, study finds

Published

18 hours ago

December 19, 2025

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Aging-related joint disorder increasingly affects people under 40, study finds

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Cases of gout are rising in younger individuals, according to a global study.

The condition, which is a type of inflammatory arthritis, steadily increased in people aged 15 to 39 between 1990 and 2021, researchers in China announced.

Although rates vary widely between countries, the total number of young people with the condition is expected to continue rising through 2035.

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The study, published in the journal Joint Bone Spine, investigated 2021 data from the Global Burden of Disease (GBD), spanning 204 countries within the 30-year timeframe.

The data measured gout prevalence, incidence and years lived with disability, tracking global trends over time. The results showed a global increase across all three outcomes.

Gout is expected to continue rising in young people through 2035. (iStock)

Prevalence and disability years increased by 66%, and incidence rose by 62%. In 2021, 15- to 39-year-olds accounted for nearly 14% of new gout cases globally, the study found.

Men from 35 to 39 years old and people in high-income regions had the highest burden, but high-income North America topped the list for highest rates.

‘SKINNY FAT’ WARNING ISSUED AS STUDY FINDS HIDDEN OBESITY BEHIND NORMAL BMI

Men were also found to have lived more years with gout due to high BMI, while women tended to have the condition as a link to kidney dysfunction, the study noted.

The total number of cases is expected to increase globally due to population growth, but the study projected that rates per population would decrease.

The researchers noted that data quality, especially in low-income settings, could have posed a limitation to the broad GBD data.

What is gout?

Gout is a common form of arthritis involving sudden and severe attacks of pain, swelling, redness and tenderness in the joints, according to Mayo Clinic. It most often occurs in the big toe.

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The condition occurs when urate crystals accumulate in the joint. These form when there are high levels of uric acid in the blood, which the body produces when it breaks down a natural substance called purines.

A gout flare-up can happen at any time, often at night, causing the affected joint to feel hot, swollen, tender and sensitive to the touch.

Urate crystals, described as sharp and needle-like, build up in the joint, causing intense pain and swelling. (iStock)

Purines can also be found in certain foods, like red meat or organ meats like liver and some seafood, including anchovies, sardines, mussels, scallops, trout and tuna, according to the Mayo Clinic. Alcoholic drinks, especially beer, and drinks sweetened with fruit sugar can also lead to higher uric acid levels.

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Uric acid will typically dissolve in the blood and pass through the kidneys into urine, but when the body produces too much or too little uric acid, it can cause a build-up of urate crystals. These are described by the Mayo Clinic as sharp and needle-like, causing pain, inflammation and swelling in the joint or surrounding tissue.

Risk factors for gout include a diet rich in high-purine foods and being overweight, which causes the body to produce more uric acid and the kidneys to have trouble eliminating it.

Experts urge patients to seek medical attention for gout flare-ups. (iStock)

Certain conditions like untreated high blood pressure, diabetes, obesity, metabolic syndrome and heart and kidney diseases can increase the risk of gout, as well as certain medications.

A family history of gout can also increase risk. Men are more likely to develop the condition, as women tend to have lower uric acid levels, although symptoms generally develop after menopause.

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Untreated gout can cause worsening pain and joint damage, experts caution. It may also lead to more severe conditions, such as recurrent gout, advanced gout and kidney stones.

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The Mayo Clinic advises patients to seek immediate medical care if a fever occurs or if a joint becomes hot and inflamed, which is a sign of infection. Certain anti-inflammatory medications can help treat gout flares and complications.

Fox News Digital reached out to the researchers for comment.

Angelica Stabile is a lifestyle reporter for Fox News Digital.

Health

New study questions whether annual mammograms are necessary for most women

Published

1 day ago

December 19, 2025

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New study questions whether annual mammograms are necessary for most women

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A new study suggests that annual mammograms may not be the only effective approach for preventing breast cancer.

The research, published in the Journal of the American Medical Association (JAMA), tested a risk-based breast cancer screening approach against standard annual mammography.

The WISDOM randomized clinical trial, led by study authors from universities and healthcare systems across the U.S., considered more than 28,000 women aged 40 to 74 years old, splitting them into a risk-based screening group and an annual mammography group.

ERIN ANDREWS HAD ‘NO SYMPTOMS’ BEFORE CANCER DIAGNOSIS, PUSHES FOR EARLY SCREENINGS

Researchers calculated each woman’s individual risk based on genetics (sequencing of nine breast cancer genes) and other health factors.

A new study suggests that annual mammograms may not be the only effective approach for preventing breast cancer. (iStock)

Those who were at the highest risk were advised to alternate between a mammogram and an MRI scan every six months. Patients with elevated risk were told to get an annual mammography and counseling.

Average-risk women were guided to get mammograms every two years, while low-risk individuals were advised to have no screening until they became higher risk or reached age 50.

HIDDEN TYPE OF BREAST CANCER COULD BE EXPOSED BY NEW BREAKTHROUGH TECH

The researchers found that risk-based screening did not lead to more advanced cancer diagnoses (stage 2B or higher) compared with annual screening, indicating that it is just as safe as traditional methods. The risk-based approach, however, did not reduce the number of biopsies overall, as researchers had hoped.

Among the risk-based group of women, those with higher risk had more screening, biopsies and detected cancers. Women at lower risk had fewer procedures.

The research, published in the Journal of the American Medical Association (JAMA), tested a risk-based breast cancer screening approach against standard annual mammography. (iStock)

“[The] findings suggest that risk-based breast cancer screening is a safe alternative to annual screening for women aged 40 to 74 years,” the researchers noted in the research summary. “Screening intensity matched individual risk, potentially reducing unnecessary imaging.”

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Fox News medical contributor Dr. Nicole Saphier, associate professor of radiology at Memorial Sloan Kettering Cancer Center in New Jersey, commented that while these findings are important, the study “completely sidelines” what screenings are designed to do — detect cancer early.

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“If you don’t measure stage 0, stage 1 or stage 2A cancers, you can’t tell whether personalized screening delays diagnosis in a way that matters for survival and treatment intensity,” Saphier, who was not involved in the study, told Fox News Digital in an interview.

Those who were at the highest risk were advised to alternate between a mammogram and an MRI scan every six months. (iStock)

More than 60% of breast cancers in the U.S. are diagnosed at stage 1 or 2A, where cure rates exceed 90%, the doctor noted.

The trial doesn’t “fully evaluate” whether risk-based screening changes detection at the earliest and most treatable stages, where screening “delivers its greatest benefit,” according to Saphier.

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“Mammography is not without risk — radiation exposure, false positives, anxiety and potential over-diagnosis are real and should be acknowledged,” she said. “But it remains the most effective, evidence-based tool for detecting breast cancer early, when treatment is most successful.”

The expert added that labeling women under 50 as “low risk” is “outdated,” as breast cancer diagnoses are on the rise in younger females.

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“Until long-term mortality data support alternative approaches, annual screening beginning at 40 for average risk women should continue,” Saphier added. “Women should be assessed for breast cancer risk by 25 years old to determine if screening should begin earlier.”

Angelica Stabile is a lifestyle reporter for Fox News Digital.