Mind Under Heat Waves

According to recent records, last year marked the hottest year in history, with Canada experiencing a temperature rise twice the global average. Interestingly, your brain has a role in helping you handle heat waves, but it requires some support as temperatures continue to climb.

Your Body’s Thermostat

At the core of your brain is the hypothalamus, which regulates your core body temperature, keeping it just right—not too hot and not too cold.

According to Dr. Arie Francis, an emergency medicine physician, “The hypothalamus maintains body temperature by receiving signals from thermoreceptors found throughout the body, adjusting temperature through various mechanisms.” For instance, if it detects overheating, the hypothalamus may prompt sweating, while feeling cold could initiate shivering to warm you up.

Unfortunately, the hypothalamus has its limits, especially when faced with extreme heat.

Heat’s Impact on Your Brain

Your brain makes concerted efforts to regulate body temperature, but excessive heat can affect it as well. Dr. Sean Ormond warns, “When exposed to high temperatures, the body focuses on cooling down, and blood flow is redirected away from the brain.”

This reduced blood circulation results in less oxygen and nutrients reaching the brain, leading to a decline in mental health and cognitive function. Many individuals “may struggle with confusion and disorientation,” explains Dr. David Tang, an emergency physician experienced in sports and exercise medicine.

Last year’s heat wave in Europe left numerous tourists confused and missing along well-marked trails, with some speculating that the heat contributed to their impaired judgment.

If heat exposure isn’t addressed promptly, serious consequences can arise. “Prolonged heat can lead to brain swelling,” adds Ormond, emphasizing the dangers of heat exhaustion and heat stroke, particularly for those with conditions like migraines and chronic pain, which can worsen in excessive heat.

Fortunately, there are proactive steps you can take to assist your hypothalamus and safeguard both your brain and body.

Protect Your Brain from Heat

“Preparation for extreme heat should begin before you even go outside,” recommends family nurse practitioner Jung Baccam.

Check the Weather

Utilize reliable sources like Environment Canada to monitor the forecast and heat index. Consider not just the temperature but also humidity levels and sun exposure.

“The risk of heat-related illnesses is greatest during periods of high humidity and prolonged sun exposure,” notes Francis. To stay safe, avoid outdoor activities from 10 am to 4 pm, when the sun is at its hottest.

Dress Smart

“Choose loose, light-coloured clothing, wear a hat, and don’t forget sunscreen,” advises Baccam.

Consider mineral-based sunscreens that can help reflect sunlight. This not only protects your skin but also aids circulation, an essential factor in temperature regulation.

Take Breaks

It’s no coincidence that many individuals in warmer climates enjoy midday rest periods. “Find opportunities to take breaks in the shade or air conditioning whenever possible,” suggests Ormond. Regularly using cooling towels or misting sprays can also be beneficial.

Recover Effectively

“Rehydrating after exposure to extreme heat is crucial,” emphasizes Ormond. Simple hydration may not suffice on exceptionally hot days. “A cool (but not freezing) shower can help bring your body temperature down gradually,” he adds, “and rest in a cooler, darker environment is essential for your brain to recuperate.”

Applying a cold cloth to pulse points like your neck and armpits can help expedite cooling due to the higher concentration of blood vessels in those areas.

A Positive Perspective on a Warm Future

“Heat waves are becoming increasingly frequent, requiring us to be more aware of their effects on our health,” states Ormond. He believes that government investment in cooling infrastructure, such as green roofs and a tree planting initiative, is critical. However, it ultimately falls on individuals to take action as well.

“Building habits that promote safety in extreme heat is essential,” he concludes. “While heat can pose risks, being attentive to your body and adhering to safety measures can help ensure your well-being—even during the hottest weather.”

This article was originally published in the June 2025 issue of alive magazine.