Insights from a workshop on climate-resilience in health systems in Japan and Germany: strategies to counteract social isolation and heat health risks for older adults.

Climate change leads to adverse health effects globally, including increased heat-related mortality of the elderly. Besides physiological factors of aging and comorbidities, social isolation is one risk factor associated with adverse health effects of heat. In 2025, the Working Group Environmental Health at Hokkaido University and the Institute of General Practice from University of Cologne held a research workshop to explore joint solutions for climate-resilience in super-aged nations like Germany and Japan. The three-day interactive workshop was held at Hokkaido University, Sapporo, Japan and included a hybrid symposium with external experts as well as intensive exchange between the research groups. Jointly addressing social isolation and heat health risks, was identified as a promising way to increase health systems resilience in times of societal and environmental crisis, especially in super-aged countries. This commentary narratively summarizes the current evidence on interventions targeting social isolation and heat health risks, finding that current interventions aim to protect socially isolated older adults during heat waves, but do not intend to alleviate both, social isolation and heat health risks at a broader scale. Based on the discussions in the workshop this commentary proposes future research opportunities, entailing family-based as well as community-based approaches, which foster social connection throughout the year and are particularly triggered during hot days and heat waves. Further research is needed to co-develop and evaluate such interventions with older adults and their families and communities to increase resilience of societies and health systems.