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