Heat’s Impact on Children’s Brain Connectivity Revealed

As global temperatures continue to rise, scientists are uncovering new ways in which heat affects not just our environment, but also our health—especially the developing brains of children. A groundbreaking study led by the Barcelona Institute for Global Health (ISGlobal) has found a concerning link between high ambient temperatures and reduced brain connectivity in preadolescents. The findings, published in the Journal of the American Academy of Child & Adolescent Psychiatry, add to a growing body of research highlighting the risks of climate change on cognitive and mental health.

How Heat Affects Brain Function in Children

The study analyzed data from 2,229 children aged 9 to 12, part of the “Generation R” cohort in Rotterdam, Netherlands. Researchers used resting-state magnetic resonance imaging (MRI) to assess how different regions of the brain communicate. They then compared this data with daily temperature estimates from the UrbClim urban climate model, assigning each child an average temperature based on their home address.

The key finding? Higher ambient temperatures in the week leading up to the MRI scan correlated with lower functional connectivity in three critical brain networks: the medial parietal network (linked to self-perception), the salience network (key for detecting and prioritizing important stimuli), and the hippocampal network (essential for memory and learning). This suggests that heat can disrupt how efficiently different parts of the brain work together, potentially impairing attention, cognitive processing, and decision-making.

Interestingly, this effect was most pronounced the day before the brain scan and gradually weakened in the following days. In contrast, lower average daily temperatures did not appear to impact functional connectivity at all.

Why Might Heat Reduce Brain Connectivity?

One possible explanation the researchers propose is dehydration. The human brain relies on proper hydration to maintain normal function, and children are particularly vulnerable to fluid loss when exposed to heat. This could explain why significant disruptions in brain network connectivity were observed following warmer days.

Laura Granés, the study’s lead researcher, explains: “We hypothesize that dehydration could explain our findings, as children are particularly vulnerable to fluid loss when exposed to heat, which can affect the functional connectivity of brain networks.”

Implications for Mental Health and Well-Being

While earlier studies have explored how extreme temperatures influence mental health, this research is among the first to directly link ambient heat exposure to changes in brain network connectivity. It raises important questions about how climate change might exacerbate existing mental health issues in young people.

Previous research from the same team found that both heat and cold exposure can influence psychiatric symptoms such as anxiety, depression, and attention disorders. Other studies have also linked reduced connectivity in the salience network specifically to serious mental health conditions like suicidal ideation and anxiety disorders.

Carles Soriano-Mas, one of the study’s authors, notes: “Given the role of the salience network in suicidal ideation, our findings raise a new hypothesis: high temperatures could decrease the functional connectivity of this network, indirectly contributing to a higher risk of suicide in individuals with pre-existing mental health conditions.”

Though the researchers stress that heat exposure alone is not likely to cause suicidal behavior, they suggest that it may act as a trigger in individuals who are already vulnerable. This finding could have profound public health implications, further underscoring the importance of protecting children from prolonged heat exposure.

The Bigger Picture: Climate Change and Public Health

Beyond individual cognitive impacts, this study adds to growing concerns about climate-related health risks. As global temperatures continue to rise, policymakers must consider how children—one of the most vulnerable populations—may be disproportionately affected.

Protecting young brains from heat requires practical public health strategies. Schools and parents should ensure children stay hydrated and have access to cool environments, especially during heat waves. Urban planners should also consider increasing green spaces and implementing cooling infrastructure to mitigate the impact of rising temperatures in cities.

Mònica Guxens, senior author of the study, emphasizes the need for action: “In the current climate emergency, public health policies aimed at protecting children and adolescents from high temperatures could help mitigate potential effects on brain function.”

Looking Ahead: What More Do We Need to Know?

While this study provides a crucial first step in understanding the connection between heat and brain function, more research is needed. Future studies could explore whether long-term exposure to high temperatures has cumulative effects on cognitive development and mental health. Additionally, scientists should investigate whether certain socioeconomic factors—such as access to air conditioning, quality of nutrition, or pre-existing health conditions—affect susceptibility to heat-related brain changes.

The intersection of climate change and neuroscience is an emerging field with significant real-world consequences. As research continues to evolve, public awareness and policy interventions will be key in ensuring that rising temperatures do not threaten children’s development and well-being.

For more details, refer to the full study published in the Journal of the American Academy of Child & Adolescent Psychiatry.