How High Temperatures Affect Your Brain

Many people love summer. However, the hottest days can become torture for those who still need to perform. In fact, your cognitive system is greatly affected by heat.
How High Temperatures Affect Your Brain
Elena Sanz

Written and verified by the psychologist Elena Sanz.

Last update: 21 December, 2022

Many people love summer. There are more daylight hours and the kind of climate that promotes socialization and outdoor leisure. In addition, for most of us, there are vacations. Therefore, you might expect that during the summer season you’d find yourself to be more rested, relaxed, and happy. So why do you sometimes feel so apathetic, irritated, and unfocused? The answer lies in the way high temperatures affect the brain.

Your body is pretty clever and knows how to adapt to different environmental conditions. However, it doesn’t like sudden changes and, during the summer, you often experience intense rises in temperature. In fact, despite your best efforts, when you approach or exceed 40 °C, your brain doesn’t function as well and you notice this in your mood and cognitive performance.

High temperatures affect your brain

If you’re someone who experiences an improvement in your mood during the summer, it’s won’t be just because you’re looking forward to your vacation. It’s due to the greater amount of sunlight at this time of year. Light increases the production of serotonin, a neurotransmitter capable of generating states of well-being, relaxation, and satisfaction.

However, excessively high temperatures can counteract these effects and cause irritability, discomfort, and fatigue.

man getting hot
Heat affects cognitive performance.

The hypothalamus and its thermoregulatory function

As we mentioned earlier, your body has its own mechanisms to adapt to environmental conditions. With regard to regulating body temperature, it’s the hypothalamus that’s in charge of this process. Through convection and sweating, it manages to maintain the appropriate 36-37 °C.

However, if you withstand ambient temperatures of more than 35-40 °C, your body has to exert extra effort which acts to the detriment of other functions. For example, your concentration and reaction rate are negatively affected and you can experience attention problems and a lack of mental clarity.

Risk of dehydration

Another way high temperatures affect your brain is through dehydration. It’s worth mentioning that 90 percent of the volume of your brain is made up of water, and this constitutes the main vehicle for electrochemical transmissions. Thus, dehydration is a risk that can cause alterations in your neuronal activity.

A two percent drop in body water is enough to produce noticeable effects, such as trouble focusing your eyes, short-term memory loss, or difficulty concentrating. In addition, it’s especially relevant if you suffer from migraines or headaches since dehydration can cause or aggravate them.

Insomnia and rest problems

Sleep is an important factor in the functioning of your brain. Quality sleep promotes memory, creative and problem-solving capacity, and helps to alleviate the mental load during periods of stress. For this reason, insufficient rest affects your cognitive performance and mood, making you feel unfocused, slow, confused, and moody.

So, how are insomnia and high temperatures related? We can all attest to how difficult it is to drop off and get a good night’s sleep when it’s too hot. This is due to cerebral hyperexcitation.

The ideal temperature for resting is around 18-21 °C. When it exceeds 26 degrees you can have real problems adapting. Consequently, it’s difficult for you to fall asleep and you may wake up multiple times throughout the night.

Tired hot woman
High temperatures are related to problems when falling asleep.

High temperatures affect your brain by altering your emotions

One last way that high temperatures affect your brain is by causing emotional disturbances. Indeed, sustained extreme temperatures have been shown to intensify negative emotions such as anxiety, stress, and irritability. They also reduce prosocial behaviors. In addition, they can generate apathy and demotivation, which leads you to miss out on opportunities to perform rewarding activities. The result is a low and negative mood.

In fact, the summer heat can affect you more than you might think at both a cognitive and emotional level. For this reason, it’s advisable to take appropriate measures. For example, avoid being outdoors at the hottest time of the day, hydrate yourself properly, and wear comfortable clothes. This will help you combat high temperatures, thus reducing the negative impact on your brain.

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All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

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The contents of Exploring Your Mind are for informational and educational purposes only. They don't replace the diagnosis, advice, or treatment of a professional. In the case of any doubt, it's best to consult a trusted specialist.