Extreme heat doesn’t just make you sweat and feel uncomfortable — it measurably changes how your brain functions. In a recent television interview, I explained why high temperatures affect your focus, your mood, and even your ability to make good decisions.
Why Does Heat Make Us Think Worse?
When it’s very hot, the body needs to cool down — and to do that, it redirects blood flow toward the skin. That means it literally takes blood flow away from vital organs, including the brain.
As I explained in the interview: “The brain suffers a lack of blood flow, which significantly affects its intellectual functions.” It’s a real physiological phenomenon, not just a feeling of discomfort.
Cortisol Comes Into Play Too
In cases of extreme heat, the body can activate a stress response and release cortisol — the same hormone that rises during other forms of stress, and that interferes with more complex brain functions.
The Brain Region That Controls Whether We’re “Pleasant”
Heat particularly affects the front part of the brain, the prefrontal cortex, responsible for emotions and complex decision-making. It’s literally the part of the brain that helps us be pleasant people and avoid saying things we later regret.
As I put it in the interview: it’s not just that we’re upset because we’re hot — it’s that the brain isn’t working at its best, and those are exactly the areas that control our personality.
Heat Also Affects Children’s Learning
This isn’t a minor issue for Miami families. Researchers at the Harvard Kennedy School analyzed millions of standardized test results and found that cumulative heat exposure reduces academic performance, with a notably larger impact on math than other subjects, especially in classrooms without adequate air conditioning.
On very hot days, especially with limited air conditioning, it’s common to notice kids (and adults) becoming more distracted and irritable.
Why Summer Is Linked to More Conflict
It’s no coincidence that conflicts, and even crime rates, tend to rise during the hottest months. The same disruption in the prefrontal cortex that makes us more irritable also reduces our ability to control impulses — a combination that can lead to more aggression and worse decisions.
What to Do on Very Hot Days
- Stay hydrated. Dehydration forces the brain to divert resources to compensate.
- Take extra precautions with children, older adults, and people with health conditions that make them more vulnerable to heat.
- Avoid making important decisions on the hottest days, if you can wait.
- Take a deep breath and drink water before reacting to something frustrating — it’s more likely the heat talking than you.
If Miami’s extreme heat is affecting you persistently — beyond what’s expected on a hot day — I invite you to schedule a consultation.
Frequently Asked Questions
Why does heat affect concentration?
Extreme heat redirects blood flow toward the skin to help the body cool down, which reduces blood flow to the brain and affects functions like concentration and decision-making.
Can heat really make us more irritable?
Yes. Heat particularly affects the prefrontal cortex, the brain region that regulates emotions and impulse control, which can increase irritability and impulsivity.
Does heat affect children’s school performance?
Studies show that prolonged heat exposure reduces academic performance, with an especially notable impact on math, particularly in schools without adequate air conditioning.
Is it a good idea to make important decisions on very hot days?
Not ideally. Heat affects the prefrontal cortex, the same region we use for complex decision-making, so it’s best to wait for a cooler day when possible.