Do you have a foggy head? Confused? Exhausted? As the temperature rises, many of us become suddenly incompetent at normally simple tasks.
And with the United Kingdom being hotter than the Caribbean this weekend, scientists say it is time to take the impact of heat on our brains more seriously.
According to Dr. Laurence Wainwright, an environmental health expert from the University of Oxford, heatwaves have a significant impact on mental health.
Heat stress impairs key regions of the brain, especially those responsible for cognitive tasks.
This weekend, the United Kingdom was hotter than the Caribbean, and scientists say it is time to take the impact of heat on our brains more seriously.
During periods of extreme heat, Dr. Wainwright also warns of the increased risk of depressive symptoms, anxiety, and disturbingly, violent attacks.
Professor Trevor Harley, a psychologist from the University of Dundee who is an expert on the behavioral effects of weather, explains: “When the external temperature exceeds 25 degrees Celsius, the brain struggles to perform complex tasks. The increased risk of suicide and self-harm is more alarming.’
So what is it about the hot weather that causes us to lose our minds?
WHY FOCUS FALLS OUT THE WINDOW
Numerous studies have demonstrated that key brain functions, such as memory, learning, and concentration, are impaired by heat.
In the summer of 2018, researchers at Harvard University in Cambridge, Massachusetts – where temperatures hit highs of more than 36C – carried out tests on two groups of students, one studying in an air-conditioned building, the other not.
Those without air conditioning performed ten to fifteen percent worse on tests of attention, working memory, and processing speed.
Other studies examining office productivity in the United States and Japan have found that concentration wanes when the outdoor temperature reaches its peak.
However, why?
Dr. Eileen Neumann, a neuroscientist from the University of Zurich, explains that the hypothalamus in the center of the brain strictly controls the core body temperature.
If it detects a rise in skin temperature, it alerts other body systems to take action to maintain a stable core temperature.
To prevent organs from overheating, this includes inducing feelings of thirst and directing blood flow toward the skin’s surface.
These processes consume a great deal of energy, nutrients, and blood flow, leaving considerably less for complex brain functions such as memory and focus.
She adds, “The brain is also especially sensitive to dehydration; even a slight lack of fluid can alter the quality of signals sent between brain cells.”
When temperatures exceed 30 degrees Celsius, a single morning without sufficient water can impair performance on a variety of cognitive tests, according to an Israeli study.
In extreme situations, heat stroke can occur. This is a medical emergency that occurs when the hypothalamus fails to prevent the body from overheating, leading to the death of brain cells.
This can occur after 30 minutes in temperatures between 30 and 40 degrees Celsius without adequate hydration, especially in those with underlying health conditions,” explains Dr. Neumann. Roughly one-fifth of heatstroke victims suffer from some form of permanent neurological damage.
The heat can induce anxiety and depression.
What are your thoughts on claims that heatwaves may trigger mental health conditions or significantly exacerbate existing ones?
In 2020, a global analysis of more than 50 studies involving 1.9 million mental health patients will conclude that the risk of developing psychiatric illnesses such as depression and anxiety increases by 0.9% for every 1C increase in temperature.
In addition to comparing climates across nations, the scientists examined the impact of mini-heatwaves in colder European climates, including the United Kingdom.
In addition, doctors in the United States have reported a significant increase in visits to emergency departments for anxiety, stress disorders, and mood disorders on days with above-average temperatures.
And in Mexico, a monthly increase of less than 1C has been linked to a 2.1% increase in suicides, according to Stanford University research.
So what is happening?
According to some scientists, it’s all due to irritability brought on by difficulty sleeping: increased sunlight during the summer months disrupts our sleep-wake cycle, thereby increasing the risk of insomnia.
But the idea that hot weather has a direct effect on the brain itself is far more intriguing.
Serotonin is essential for maintaining a stable mood and regulating sleep, but it is disrupted by high temperatures.
Even though studies indicate that levels of the hormone tend to be higher when the weather is extremely warm, this does not necessarily mean that we are happier.
Brain scans conducted by researchers at the University of Copenhagen revealed an increase in proteins that collect and deactivate excess serotonin.
This decreases the amount of active serotonin, increasing the likelihood of experiencing low or unstable moods.
‘We know that even the smallest fluctuation in activity levels can have a significant effect on mood,’ says Prof Harley.
SPARKS CAN FLY WHEN TEMPERATURES SOAR
Long have psychologists pondered why the number of violent crimes seems to skyrocket during heatwaves.
According to Dr. Wainwright, even a 1C to 2C increase in typical monthly temperatures can result in a five to ten percent increase in assaults.
There are some clear hypotheses, such as the notion that people are more inclined to consume alcohol or become irritable when the temperature is high.
However, according to Professor Harley, the explanation also resides in a change in our brain chemistry.
He says that excessive heat triggers an increase in cortisol, the stress hormone secreted by the hypothalamus as part of its effort to regulate body temperature.
Its surge activates the ‘fight or flight response,’ the body’s natural response to threats that induces a rapid heartbeat and increased blood flow to the legs and arms in preparation for an assault.
However, research indicates that an abundance of cortisol increases our likelihood of engaging in impulsive and aggressive behavior.
Dr. Harley suggests that this may interact with serotonin disruption to raise the chance of additional symptoms, such as worrying thoughts and poor mood.
THOSE ON MEDICINES FOR MENTAL HEALTH SHOULD BE CAREFUL
Experts are eager to alert psychiatric medication users of the potential dangers to their physical health in hot areas.
Certain medications, such as clozapine and olanzapine, used to treat schizophrenia and psychosis symptoms, as well as bipolar disorder and dementia, have a direct effect on the hypothalamus.
As a result, they can prevent the brain from efficiently detecting when we are too hot.
Patients taking these medications may be less able to detect thirst, increasing their risk of dehydration.
Prof. Harley states, “We should consider sun safety crucial not just for the protection of our skin, but also our mental health.”
The same rules apply to the brain: stay out of the midday sun and drink plenty of water.
