Air Conditioning as a Climate Adaptation Strategy for Sleep Disturbances: A Data-Driven Approach

Several epidemiological studies suggest that climate change-induced increases in nighttime temperatures may significantly affect sleep quality. While air conditioning (AC) is considered a key adaptation, its effectiveness has only been tested in small-scale experiments, limiting its generalizability. To address this gap, we conducted a large-scale epidemiological study to quantify the impact of AC on sleep and analyzed the results using machine learning.

Our study surveyed more than 2,000 residents of Nagoya, Japan, during the summers of 2011 and 2012 and the winter of 2023, with each survey lasting approximately 10 days. Data collected included the Pittsburgh Sleep Quality Index (PSQI), the Revised Sleep Quality Index for Daily Sleep (SQIDS2), indoor temperature and humidity, AC use, stress levels, alcohol consumption, etc. Increases in nighttime temperatures due to climate change may significantly affect sleep quality. Outdoor temperature data were obtained from meteorological stations located near the residents. The collected data were analyzed using the gradient boosting method LightGBM and SHapley Additive exPlanations (SHAP) to assess the relationship between AC use and sleep quality.

The findings revealed that the effectiveness of AC varied between individuals. In summer, optimal sleep quality was associated with an AC temperature setting of approximately 27°C, while in winter, continuous overnight AC operation was beneficial. These results provide scientific evidence for effective AC management strategies to mitigate climate change-related sleep disturbances and support future climate adaptation efforts.