A team of scientists examined data from 19,607 children aged three to four years in six countries, including Gambia and Palestine. Their goal was to assess how exposure to high temperatures affects fundamental skills.
The analysis shows that when the average maximum temperature exceeds 30 degrees Celsius (86 degrees Fahrenheit), the probability of achieving literacy and numeracy milestones decreases by 5 to 6.7%. This correlation was established by comparing children living in similar climatic conditions but with heat differences.
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Moreover, children from economically modest families or living in urban areas experience more pronounced delays. Limited access to drinking water or suitable housing amplifies these difficulties, indicating that existing inequalities can be exacerbated by heat.
To conduct this investigation, researchers used the Early Childhood Development Index, a standardized tool measuring several domains such as academic skills and behavior. They combined this data with demographic information and monthly temperature records.
These observations prompt a rethinking of child protection measures in the face of a warming climate. The authors, including Jorge Cuartas, indicate in the
Journal of Child Psychology and Psychiatry that additional studies are needed to identify the precise mechanisms behind these effects.
The biological mechanisms of heat on the brain
Excessive heat can disrupt brain function in several ways. When the body is exposed to high temperatures, it must work harder to maintain its internal temperature, which can reduce blood flow to the brain. This limits the supply of oxygen and essential nutrients to nerve cells, thus affecting concentration and memory.
In young children, whose brains are still developing, these disturbances can have lasting consequences. Neurons are particularly sensitive to environmental stressors, and repeated exposure to heat could slow the formation of new synaptic connections. These processes are fundamental for acquiring skills such as reading and arithmetic.
Moreover, heat can influence the levels of certain neurotransmitters, such as serotonin, which play a role in mood and learning. Extreme temperatures can cause fatigue, irritability, or sleep disorders, all factors that harm children's ability to concentrate and learn effectively.
Understanding these mechanisms helps to imagine interventions, such as improving ventilation in schools or access to cool spaces. It also shows why disadvantaged children, often exposed to poorer living conditions, are more vulnerable to these effects.