Summer heat has swept the U.S., with warnings issued across the East Coast and Midwest.

In addition to putting stress on the body, hot weather can also take a toll on the brain and mental health.

Dr. Jace Reed, director of emergency psychiatry at Cedars-Sinai Hospital in Los Angeles, emphasized in an interview with Fox News Digital that the brain is a major organ that can be greatly affected by heat.

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Extreme heat can cause mental health changes like increased irritability and anxiety, along with decreased memory, attention and reaction time.

This can affect daily interactions socially and professionally, the expert cautioned.

“You may be slower at completing your task or remembering what someone just told you,” he told Fox News Digital. “Those can be initial early signs that the heat is affecting your brain and your mental abilities.”

Symptoms like extreme confusion could mark the beginning of a heat stroke, which could require hospitalization, the psychiatrist warned.

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In a separate interview with Fox News Digital, Thea Gallagher, a doctor of psychology and director of wellness programs at NYU Langone Health, noted that when the body overheats, it struggles to regulate internal balance.

This can lead to disrupted sleep, fatigue and poor concentration, as well as impaired cognitive function, slow reaction times and struggles with decision-making.

Extreme heat can cause slower cognitive function, along with delays in reaction times and decision-making. (iStock)

The heat can also increase oxidative stress and inflammation in the brain, Gallagher added, which can potentially damage neurons, worsen existing neurological conditions and raise stroke risk.

“Heat exposure may trigger an inflammatory response in the brain,” she said. “In cases like heatstroke, inflammation is believed to contribute to symptoms such as confusion and delirium.”

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Excessive heat can also weaken the protective blood-brain barrier, according to the expert, which makes the brain more vulnerable to toxins and pathogens.

Higher temperatures are also associated with disturbances in mood and violent behavior, especially during prolonged heatwaves.

Emergency visits for mental health concerns rise during hotter days, according to experts. (iStock)

Psychiatric emergency visits for anxiety, depression and substance use also rise significantly on the hottest days, Gallagher confirmed.

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Below are some of the main mental symptoms that can worsen in hot weather, experts cautioned.

• Irritability, anxiety or mood swings
• Difficulty concentrating, or “brain fog”
• Increased impulsivity or aggression
• Worsening of psychiatric symptoms like depression or psychosis
• Confusion or delirium, particularly during heat stroke

People who suffer from mental health conditions such as mood disorders, schizophrenia, anxiety or even dementia are more vulnerable in hot weather.

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Some psychiatric medications could make it difficult for the body to regulate temperature or stay hydrated, Gallagher noted, while heat can “intensify” symptoms like agitation or paranoia.

“People with cognitive impairments may not recognize the signs of overheating,” she added.

It’s important to have patience with yourself and others on hot days, one psychologist advised. (iStock)

“Some SSRIs (selective serotonin reuptake inhibitors) can suppress sweat production, which is the body’s primary cooling mechanism. This raises the risk of overheating, dehydration and even heat stroke.”

“Paradoxically, SSRIs can also cause excessive sweating in some individuals — a side effect known as ‘SSRI sweats,’” she went on. “While this might seem like it would help with cooling, it can actually lead to dehydration if fluid intake doesn’t keep up.”

Protecting brain health

The experts recommended the following practices to protect brain health in extreme heat.

• Stay hydrated, as dehydration worsens cognitive decline
• Avoid peak heat hours; stay indoors or in shaded areas from 11 a.m. to 4 p.m.
• Use fans, air conditioning or cool showers
• Use blackout curtains and cooling bedding to ensure restful sleep
• Ask your doctor if any medications may increase heat sensitivity
• Use deep breathing and relaxation techniques to help manage heat-induced stress
• Stay socially connected; check in with friends and family

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“Days are also longer and there are more activities, which can be exhausting,” Gallagher noted. “Therefore, it is good to prioritize sleep and rest … and [find] ways to slow down when you can.”

A vaccine ingredient is in the spotlight this week, as a preservative called thimerosal was included on the agenda for a meeting of the CDC’s Advisory Committee on Immunization Practices (ACIP).

“Presentation regarding thimerosal in vaccines” was listed as an agenda item for Thursday, June 26, followed by “Proposed recommendations regarding thimerosal-containing influenza vaccine.”

Thimerosal (also spelled thiomersal) is a mercury‑based preservative that has been used in multi-dose vaccines and medications since the 1930s as a means of preventing contamination, according to the CDC.

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The ingredient is intended to prevent contamination by stopping the growth of bacteria and fungi, the same source states.

Due to growing concerns about potential mercury exposure, the American Academy of Pediatrics, Public Health Service agencies and vaccine manufacturers agreed that thimerosal should be “reduced or eliminated in vaccines.”

In 2001, thimerosal was removed from all vaccines recommended for children 6 and younger — except for influenza.

Today, multi-dose flu vaccines still contain thimerosal, but other versions are available without the ingredient.

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At the June 27 meeting, the CDC’s Advisory Committee on Immunization Practices voted to recommend that all adults (including pregnant women) and all children 18 years and younger should receive seasonal influenza vaccines only in single-dose formulations that do not contain thimerosal, according to meeting notes published by the CDC.

The CDC’s Advisory Committee on Immunization Practices voted to recommend that all adults (including pregnant women) and all children 18 years and younger should receive seasonal influenza vaccines only in single-dose formulations that do not contain thimerosal. (iStock)

Despite these recommendations, the CDC and other health agencies have claimed there is no evidence that thimerosal poses health risks.

“Thimerosal use in medical products has a record of being very safe,” the agency’s website states. “Data from many studies show no evidence of harm caused by the low doses of thimerosal in vaccines.”

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Dr. Jacob Glanville, CEO of Centivax, a San Francisco biotechnology company, reiterated that American children have not been receiving thimerosal for over 20 years in their vaccines, but that it remains in some multi-use vial vaccines, mostly outside the U.S.

Today, multi-dose flu vaccines still contain thimerosal, but other versions are available without the ingredient. (Reuters)

“We support any effort to remove it entirely — there are other preservatives that are not based on mercury,” Glanville told Fox News Digital. 

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Glanville noted that his company’s vaccines never contain mercury, aluminum, formaldehyde, or pig- or cow-derived materials.

Illegal disposable e-cigarettes, also known as vapes, may present a greater danger than traditional cigarettes, according to a study from the University of California (UC) Davis.

The research, published in the journal ACS Central Science, found that hazardous levels of several toxic heavy metals in illegal vapes could present a high cancer risk.

Researchers used a special instrument to test the puffs from three popular vape brands — ELF Bar, Flum Pebble and Esco — that are not FDA-authorized for use in the U.S., but are widely sold by retailers.

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Three heavy metals — lead, nickel and antimony — were detected in all heavily flavored and lightly flavored devices that were tested. 

These metals are classified as carcinogens, potentially leading to various types of cancers, such as skin, lung and kidney, according to the National Institutes of Health (NIH). 

All vapors exceeded the cancer risk limits for nickel, which has been linked to cardiovascular disease, asthma, lung fibrosis and respiratory tract cancer, per NIH.

Brett Poulin, senior study author and assistant professor at the UC Davis Department of Environmental Toxicology, told Fox News Digital that he was shocked at the levels of toxic metals.

“When I analyzed the first samples, the lead concentrations were so high that I genuinely thought the instrument was broken,” he said. “The levels far exceeded anything in our past data, or even the published literature.”

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One of the brands tested exposes users to as much lead as smoking 19 packs of cigarettes, the researchers discovered.

Additionally, most of the disposable e-cigarettes tested in the study were found to contain greater levels of metals and metalloids than older refillable vapes.

After evaluating about a week’s worth of puffs, the researchers determined that lead, nickel and antimony were detected in all tested vapes. (iStock)

At one point, Poulin said, he physically opened a device and discovered that it was using leaded copper alloys, which are metals made primarily of copper with small amounts of lead.

“These materials leached dangerous levels of lead into the e-liquid, even without the device being used,” Poulin told Fox News Digital.

“It remains unclear whether this was an intentional design choice, a cost-cutting measure or a manufacturing oversight.”

“This neurotoxin poses serious health risks, particularly to children and adolescents.”

There is no known safe level of lead exposure, according to Poulin.

“This neurotoxin poses serious health risks, particularly to children and adolescents, who are especially vulnerable.”

Daniel Sterman, M.D., director of the Pulmonary Oncology Program at the NYU Langone Perlmutter Cancer Center, told Fox News Digital that the study “clearly” demonstrates high concentrations of metal.

Men were found to be more likely to vape than women, according to the CDC. (iStock)

“There are several health risks of vaping that we enumerate for our patients and their family members, [such as] risks of various lung diseases, including asthma, COPD and lung cancer,” said Sterman, who was not involved in the study.

The doctor noted that while it is challenging to establish a direct link of causation between disposable vapes and cancer, he does see cancer patients who use the devices.

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“Disposable vapes should be highly regulated by local, state and federal agencies, and restricted to those individuals 21 years or older,” Sterman recommends.

The doctor also called for the packaging on disposable vapes to clearly outline the many health risks, “particularly to teenagers and young adults.”

Potential limitations

One of the primary limitations of the study was that only three disposable e-cigarette brands were tested out of the hundreds currently on the market. 

There are distinct differences in the metal leaching and profiles across all three brands, Poulin shared. 

The Center for Disease Control (CDC) found that the percentage of adults who used electronic cigarettes increased from 4.5% in 2019 to 6.5% in 2023. (iStock)

“We still know very little about the metal content in the vast majority of untested disposable e-cigarette products,” he said. “This gap in knowledge poses a significant public health concern, especially given the popularity of these devices.”

A spokesperson for the China-based brand, ELFBAR, told Fox News Digital that they refute the results of the study, claiming that they stopped shipments in May 2023.

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Due to ongoing trademark litigation, they are unable to market or sell products in the U.S., the company stated.

“This market void has led to a surge in counterfeits, imitations and illicit variations misusing our brand name,” the spokesperson said. “As such, we have every reason to believe the devices tested in this study are not genuine and were not manufactured by ELFBAR.”

Many disposable vapes that are not FDA-authorized for use in the U.S. are widely sold by retailers. (Mike Kemp/In Pictures via Getty Images)

The spokesperson acknowledged that smoking remains the leading cause of preventable death and disease worldwide, noting that the recent study “continues to undermine public understanding of smoking cessation.”

The other two brands tested in the study did not respond to requests for comment.

“Disposable vapes should be highly regulated by local, state and federal agencies and restricted to those individuals 21 years or older.”

Electronic cigarette use among adults increased from 4.5% in 2019 to 6.5% in 2023, according to the U.S. Centers for Disease Control and Prevention (CDC).

Men are more likely to vape than women, while 15.5% of young adults between the ages of 21 and 24 reported using e-cigarettes, the above source states.

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The UC Davis study received support from the University of California Tobacco-Related Disease Research Program Grant and the California Agricultural Experiment Station.

Heart attack deaths have plummeted in recent years — but other types of cardiovascular disease still pose a major threat.

A new study by the American Heart Association (AHA) found that overall heart disease-related death rates have declined by 66%, and heart attack deaths have dropped by almost 90%.

While heart attacks are no longer the most fatal form of heart disease, there have been increases in other types — heart failure, arrhythmias (irregular heartbeats) and hypertensive heart disease (long-term high blood pressure).

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The findings were published in the peer-reviewed Journal of the American Heart Association.

In the study, researchers analyzed more than 50 years of data from the U.S. Centers for Disease Control and Prevention (CDC), focusing on heart disease deaths among adults aged 25 and older.

In 1970, heart attacks — also known as ischemic heart disease — represented more than half (54%) of all heart disease deaths, the study found.

As of 2022, only 29% of heart disease deaths were caused by heart attacks.

Other types of heart disease deaths — such as heart failure, hypertensive heart disease and arrhythmia — have risen during that timeframe, however.

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In 2022, these other types were responsible for 47% of heart disease deaths, up from just 9% in 1970, the study found.

“This distribution shift in the types of heart disease people were dying from the most was very interesting to us,” said the study’s first author, Sara King, M.D., a second-year internal medicine resident in the department of medicine at Stanford School of Medicine in Stanford, California, in the release. 

While heart attack deaths have declined, other types of heart disease deaths — such as heart failure, hypertensive heart disease and arrhythmia — have risen in the last 50 years. (American Heart Association)

“This evolution over the past 50 years reflects incredible successes in the way heart attacks and other types of ischemic heart disease are managed,” she went on.

“However, the substantial increase in deaths from other types of heart conditions, including heart failure and arrhythmias, poses emerging challenges the medical community must address.”

“The increase in other types of heart disease leading to death has offset the wins from deaths from heart attacks declining.”

Arrhythmias, or irregular heartbeats, happen when electrical impulses to the heart are too fast, slow or erratic, according to the AHA. One common example of an arrhythmia is atrial fibrillation (AFib), which begins in the upper chambers of the heart.

Heart failure is defined as a “chronic condition where the heart is unable to pump enough blood to meet the body’s needs for blood and oxygen.”

One common example of an arrhythmia is atrial fibrillation (AFib), which begins in the upper chambers of the heart. (American Heart Association)

Hypertensive heart disease describes damage to the heart caused by long-term, unaddressed high blood pressure, the AHA stated.

Sadiya S. Khan, MD, a cardiologist and associate professor at Northwestern University in Chicago, was not involved in the study but commented on the “important analysis.”

“Fortunately, this study suggests important progress in a preventable cause of death — heart attacks,” she told Fox News Digital.

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“Unfortunately, it suggests that there is a smoldering crisis of other types of heart disease deaths that may be in part related to heart attacks, but speak to the growing burden of obesity that results in more heart failure and arrhythmia-related deaths.”

“The increase in other types of heart disease leading to death has offset the wins from deaths from heart attacks declining.”

Why the decrease in heart attacks?

The researchers presented several possible reasons for the decrease in heart attack deaths, primarily advancements in treatment for sudden and acute cardiac events.

“From the establishment and increased use of bystander CPR and automated external defibrillators (AEDs) to treat cardiac arrest outside the hospital setting, to the creation of systems of care that promote early recognition of and quick procedural and medical intervention to treat heart attacks, there have been great strides made in helping people survive initial acute cardiac events that were once considered a death sentence,” King said in the release.

“The next frontier in heart health must focus on preventing heart attacks, and also on helping people age with healthier hearts and avoiding chronic heart conditions later in life.” (iStock)

The researchers also touted several other medical advancements, including coronary artery bypass grafting, cardiac imaging and many new heart disease medications.

Healthy lifestyle modifications, such as quitting smoking, exercising regularly and managing cholesterol and blood pressure, have also contributed to the reduced heart attack deaths, the AHA report stated.

Khan added, “It is important to note that this doesn’t mean the heart attack may still not have been the driver, if someone with a heart attack developed heart failure and that is now called a heart failure death.”

Risk factors remain

Despite the improvements, the researchers cautioned that several other heart disease risk factors — including obesity, type 2 diabetes, hypertension and physical inactivity — are still fueling cases.

Obesity in particular has risen from 15% to 40% during the study timeframe, and type 2 diabetes affects nearly half of U.S. adults, according to the report.

Increased life expectancy is another factor — as people are living longer, a larger aging population is more likely to experience various types of heart disease.

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“We’ve won major battles against heart attacks; however, the war against heart disease isn’t over,” King said. “We now need to tackle heart failure and other chronic conditions that affect people as they age.”

“The next frontier in heart health must focus on preventing heart attacks, and also on helping people age with healthier hearts and avoiding chronic heart conditions later in life.”

The AHA calculates heart health based on an individual’s score for what it calls “Life’s Essential 8.” Those who score high in those eight areas are, on average, six years younger biologically than their actual age.  (American Heart Association)

The AHA calculates heart health based on an individual’s score for what it calls “Life’s Essential 8.”

Those who score high in those eight areas are, on average, six years younger biologically than their actual age. 

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The eight lifestyle behaviors for optimal heart health are listed below.

1. Eat better
2. Be more active
3. Quit tobacco
4. Get healthy sleep
5. Manage weight
6. Control cholesterol
7. Manage blood sugar
8. Manage blood pressure

Potential limitations

The researchers pointed out several limitations of their study, including that they did not analyze data by age, sex, race, ethnicity, region or urbanization.

There could also be potential inconsistencies and “miscoding” of data over the years, they noted.

“We’ve won major battles against heart attacks; however, the war against heart disease isn’t over.”

It’s also possible that the “true burden” of heart attacks is “underestimated” in the findings, according to the researchers.

“Certain conditions including heart failure, cardiomyopathy and arrhythmias — and, in particular, ventricular arrhythmias and cardiac arrest — may be overly simplistic,” they wrote. “Many of these cases likely have underlying causes that cannot be precisely differentiated using current or past ICD (International Classification of Diseases) codes.”

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Khan pointed out that despite the decrease in direct heart attack deaths, heart disease overall is still the leading cause of mortality in the U.S., accounting for more than 900,000 deaths in 2022.