New heatwave approaching. Better be prepared for it. But the arrival of hot weather doesn’t just disrupt our days or our transportation. When temperatures remain high at night (as in the case of tropical nights), sleep becomes more difficult, more fragmented and less restorative. Result: over the shortened nights, our brain also begins to show signs of fatigue and overheat. Irritability, difficulty concentrating, memory problems… The consequences are far from trivial. Here’s what you need to know.
Heat puts pressure on the brain
As explained by Dr. Gérald Kierzek, medical director of True Medical, when the thermometer rises, the brain must make additional efforts to help the body maintain a stable temperature.
“When it’s very hot, your brain also experiences stress. Cortisol increases, which makes you more irritable”explains the expert.
This combination of heat and lack of sleep promotes what experts sometimes call “brain fog.” Concretely, several cognitive functions are affected:
- Concentration becomes more difficult;
- We forget simple information;
- The time for reflection lengthens;
- Reactions become more impulsive.
According to the doctor, prolonged exposure to high temperatures could even alter certain connections between nerve cells and disrupt the regulation of emotions.
And, unluckily, just one bad night is enough to affect your abilities, making you moody, less attentive, irritable and prone to mistakes. “These symptoms are linked to the brain’s reduced recovery during deep sleep, an essential phase for memory, attention and emotional regulation.”
Several hot nights: consequences that accumulate
When the episode is temporary, it is possible to quickly return to normal. The real problem appears when temperatures remain high for several days in a row, especially during heatwaves.
“Sleep becomes fragmented and unrefreshing. You wake up already tired, less able to think clearly,”
emphasizes Dr. Kierzek.
After several short nights, various problems can set in:
- Persistent irritability;
- Less patience;
- Greater emotional vulnerability;
- Difficulty stepping back and thinking calmly;
- Learning and memorization disorders.
In certain fragile people, this accumulation of fatigue could also promote the appearance of a depressive syndrome or aggravate already existing psychological disorders.
More serious risks for brain health
The effects of heat-related sleep deprivation on the brain are not limited to fatigue or mood swings.
Several scientific studies show that particularly hot nights are associated with an increased risk of stroke. Dehydration, sleep disturbances and stresses imposed on the cardiovascular system could explain this phenomenon.
Another area of concern: the long-term effects on cognitive abilities.
Researchers observe that repeated exposure to high temperatures could accelerate the decline of memory and intellectual functions, particularly in the elderly and the most vulnerable populations.
The cause: a progressive accumulation of inflammation, oxidative stress and micro-damage at the brain level. Ultimately, this phenomenon could contribute to reducing what specialists call “cognitive reserve”, that is to say the brain’s capacity to compensate for the effects of aging.
8 useful tips to sleep better despite the heat
Very good, but what to do against this merciless weather? Even if we cannot act on the thermometer, a few simple reflexes can limit the impact of heat on sleep. And to hope for a more bearable night.
Take a lukewarm shower before bed
“Take a lukewarm shower before going to bed. This helps cool your body without causing thermal shock. The drop in body temperature also makes it easier to fall asleep,” advises the doctor.
Hydrate regularly
Keep a cool bottle of water on hand so you can drink if needed during the night.
Choose suitable bedding
Choose light cotton sheets and avoid thick blankets which promote perspiration.
Circulate the air
When the outside temperature drops, open the windows opposite the home to create a natural draft.
Use a fan wisely
“You can also use a fan to circulate the air in the room. Placing a bottle of ice water in front of it will have an added cooling effect.”
Keep your home cool during the day
Close shutters and curtains in the morning to limit the entry of heat.
Eat light in the evening
Raw vegetables, fruits and cold soups are preferred. Rich in water, they also promote hydration.
Refresh your skin before sleeping
“Moisten your body with a mist or wet cloths before going to bed,” finally recommends Dr. Kierzek.
Simple actions that can make all the difference when tropical nights set in and the brain, too, needs to recover.