Heat Linked to Sleep Disruptions in Dutch Adolescents

High temperatures are known to disrupt sleep in adults, but their impact on younger populations remains insufficiently studied. To address this issue, a team from the Barcelona Institute for Global Health (ISGlobal), a center supported by the ”la Caixa” Foundation, investigated how elevated nighttime temperatures affect sleep and daytime sleepiness in preadolescents, using data from two European birth cohorts. The results have been published in Environment International.

The study assessed sleep patterns in 3,340 preadolescents (age range 10 to 17 years) from the Dutch Generation R study and 587 participants (age range 10 to 18 years) from the Spanish INMA Project. In the Netherlands, warmer nights were linked to shorter sleep duration and lower sleep efficiency, whereas no significant effects were observed in Spain. These findings suggest potential cross-country differences in how ambient temperature impacts sleep health.

Nighttime ambient temperatures at participants’ home addresses were estimated using the urban climate model UrbClim. Sleep characteristics were measured using a wrist-worn accelerometer worn for up to nine nights. The parameters analyzed included total sleep time, sleep latency (the time it takes to fall asleep), wake after sleep onset, and sleep efficiency.

Most sleep measurements were taken in the spring for Generation R participants and in the autumn for those in the INMA Project, while measurements were lacking in summer. Daytime sleepiness was assessed using self-reported questionnaires, mainly administered in summer for Generation R and in spring for INMA.

Reduced Sleep Duration and Efficiency

In the Generation R cohort, higher nighttime temperatures were associated with a reduction in total sleep time, specifically 5.5 minutes less for every 5°C increase. Sleep efficiency also decreased with each 5°C rise. These effects were slightly more pronounced during warmer months and among participants living in neighborhoods with lower socioeconomic status. No significant associations were found with sleep latency or wake after sleep onset.

In contrast, in the INMA cohort, no associations were observed between higher nighttime temperatures and sleep characteristics in preadolescents. Nor were there any effects on daytime sleepiness in either cohort.

"These results suggest that one population could be more adapted to heat than another. However, such comparisons must be interpreted with caution, as there are differences in the context of climate and the population. In Spain, measurements were mostly taken in autumn, when the average temperature was 13.4°C, which may explain the lack of significant associations in the Spanish cohort." explains Esmée Essers, ISGlobal researcher and first author of the study.

"Our findings indicate that climate change could negatively affect sleep health in preadolescents, highlighting the need for strategies to protect nighttime rest. These strategies can range from individual interventions, such as using appropriate bedding or cooling techniques, to broader social measures, like improving housing conditions and implementing climate policies. Reducing exposure to nighttime heat from an early age could help prevent long-term negative effects on both physical and mental health," emphasizes Mònica Guxens, ICREA researcher at ISGlobal and senior author of the study.
 

Reference

Essers, E., Granés, L., Botella, N., Petricola, S., González-Safont, L., Arregi, A., Vegas, O., Vrijheid, M., Iñiguez, C., El Marroun, H., Tiemeier, H., Guxens. M. Exposure to high temperature and sleep in preadolescents from two European birth cohorts. Doi: 10.1016/j.envint.2025.109543