Matthaios (Mat) Santamouris
Prolonged exposure of the human body to heat may result in a partial or complete inability to regulate its temperature, potentially leading to serious physiological dysfunctions, mental health issues, and even life-threatening heat strokes. Recent research indicates that long-term exposure to excessive heat impairs overall cognitive performance by affecting working memory and knowledge retention (1).
Extended exposure of students to heat, combined with demanding cognitive tasks, negatively impacts their intellectual, educational, and professional performance. This occurs through the deregulation of body temperature and alterations in brain chemistry and electrical properties (2).
Humans possess a ‘cognitive reserve’—an adaptive mechanism linked to psychological and physiological factors that helps maintain high cognitive function. However, once this reserve is exceeded, cognitive performance declines rapidly. Performance is influenced by the complexity of the task, as different regions of the brain handle distinct cognitive activities. Therefore, under identical temperature conditions, students’ cognitive performance varies depending on the nature of the task.
Relevant studies have concluded that students exposed to heat during the four years leading up to their exams experience a causal and statistically significant decline in cognitive performance and capital accumulation. An additional day of high temperatures within this period has been shown to significantly impair their cognitive function.
Studies involving several million students in the USA and other countries have provided substantial evidence that long-term heat exposure has significant social and economic implications, disproportionately affecting low-income and minority students. The disparities in heat protection measures between schools in wealthy and poor regions, as well as across countries, contribute to pronounced racial inequalities. Notably, cognitive losses in Black and Hispanic students in the USA after prolonged heat exposure were nearly three times higher than those observed in white students (3).
The anticipated rise in global temperatures is expected to exacerbate existing vulnerabilities worldwide, potentially deepening the disparities in cognitive capacity between wealthy and poor countries, as well as between affluent and disadvantaged population groups within individual nations.
With the significant rise in ambient temperatures due to global and local climate change, it is projected that students’ future cognitive performance could decline substantially if adaptation measures are not implemented. Future projections indicate that by 2050, an expected temperature increase of 1.5°C in the USA could reduce the cognitive capacity and performance of elementary school pupils by 9.8%, assuming no additional adaptation measures are implemented in schools.
The use of air conditioning in classrooms continues to be a contentious issue. Research has shown that, when properly implemented, air conditioning can improve students’ cognitive performance. However, studies conducted primarily in tropical and cooling-dominated climates indicate that the effective use of passive cooling measures can achieve comparable cognitive benefits to those provided by air conditioning.
However, it is essential to ensure proper ventilation in classrooms to prevent an unnecessary rise in CO2 levels. The use of air conditioning without adequate ventilation can have a detrimental impact on students’ health and cognitive performance, as elevated indoor carbon dioxide levels significantly impair cognitive capacity
Air conditioning is highly energy-intensive, making improvements in classroom energy efficiency a crucial prerequisite for the installation of A/C systems that provide cooling and fresh air for students. Proper ventilation in classrooms has been shown to enhance students’ learning performance. Conversely, inadequate ventilation rates have been linked to reduced attention spans, diminished ability to concentrate, and higher absenteeism.
There are significant concerns that a potential decline in the cognitive performance of younger generations could impede the future progress of nations, resulting in profound economic, social, and cultural consequences. This decline is also expected to disproportionately affect low-income populations, both within and across nations, intensifying inequality and reducing quality of life.
To safeguard the future of human capital, nations must prioritize the development and implementation of effective policies and adaptive technologies to mitigate the adverse effects of rising temperatures.
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