A tale of two temperature extremes: exploring how exposure to extreme heat or cold affects mental health and wellbeing in the UK

Monika Walia , Benedict W. Wheeler, Anne Cleary

Background and Objective

The UK's climate change vulnerability to extreme temperatures, hotter summers and milder winters, and emerging evidence on climate change and mental health require further empirical research. Therefore, this study aims to investigate the relationship between exposure to extreme temperatures and mental health and wellbeing outcomes across the UK. We also examined whether this relationship is modified by a range of factors such as sex, age, education, and social support.

Materials and Methods

We linked geographical data on daily temperatures to 10 waves of the UK Household Longitudinal Survey (2009-2019) based on residence location at each wave. Individual exposure was defined as experiencing extreme heat or extreme cold for 4+ days in the preceding four weeks. Outcomes included mental health and subjective wellbeing (SWB). Mixed-effects models were fitted, and effect modification analysis was conducted to unpack factors moderating the association with heat/cold.

Results

Exposure to extreme heat during the previous month was associated with increased risk of poor mental health (AOR (95% CI): 1.12 (1.06-1.17)) and risk of poor SWB (1.08 (1.02-1.14)) compared to those who were unexposed. However, exposure to extreme cold was associated with decreased risk of poor mental health (0.82 (0.77-0.87)). There was limited evidence for effect modification, which was inconsistent between outcomes and heat/cold exposure. Association between extreme heat and poor mental health and SWB was weaker amongst individuals with high social support and high levels of pro-environmental behaviours practised, respectively, suggesting they operate as protective factors.

Conclusion

These findings underscore the need for developing targeted interventions to enhance adaptive capacity against extreme heat. The positive association between extreme cold and mental health was unexpected and warrants further exploration. This study lends weight to indications that fostering social support and pro-environmental behaviours may help build community mental health resilience to extreme temperatures.