Climate and Health
Our environment is rapidly changing, with shifting climate patterns leaving noticeable impacts. Extreme weather conditions – such as rising temperatures and heat, severe cold spells, and fluctuating rainfall – are exacerbating the causes and effects of various health issues, from asthma and allergies to heart attacks, strokes, and metabolic disorders like diabetes. At Helmholtz Munich, we investigate the complex interplay between climate and human health. By analyzing data from Germany's largest population-based health study, which includes millions of samples, we strive to develop solutions to the significant health challenges posed by climate change.
Our environment is rapidly changing, with shifting climate patterns leaving noticeable impacts. Extreme weather conditions – such as rising temperatures and heat, severe cold spells, and fluctuating rainfall – are exacerbating the causes and effects of various health issues, from asthma and allergies to heart attacks, strokes, and metabolic disorders like diabetes. At Helmholtz Munich, we investigate the complex interplay between climate and human health. By analyzing data from Germany's largest population-based health study, which includes millions of samples, we strive to develop solutions to the significant health challenges posed by climate change.
Climate and climate change affect our environment and health. We explore the intersections between environment and human health and develop solutions for a healthier future.
![["Structure Reference Image","Structure Reference Image","Reference Image","Generated image"]](https://images.admiralcloud.com/v5/deliverEmbed/905089a2-b997-4f51-904b-2e1d5f153617/image_webp/cropperjsfocus/464/192/0,0,1920,1097,0,1,1/960,548.4999999999999?poc=true "Heat – when temperatures become a problem. Hitze – wenn die Temperaturen zum Problem werden.")
"Heat clearly highlights the limits of our human ability to adapt. When body temperature reaches 42 degrees Celsius, it becomes increasingly difficult for the medical sector to provide effective care. That’s why we must not only adapt and implement comprehensive heat protection plans, but also actively combat climate change."
Prof. Claudia Traidl-Hoffmann, Director of the Institute of Environmental Medicine
"Heat affects persons with type 2 diabetes, especially older patients. More green spaces and clean air reduce disease severity."
Prof. Annette Peters, Director of the Institute of Epidemiology
"High temperatures affect our health. Recent evidence shows that, in addition, day-to-day temperature changes can lead to hospital admissions for cardiovascular diseases."
Dr. Alexandra Schneider, Deputy Director of the Institute of Epidemiology
"Social factors like income, education, profession, living situation or social isolation as well as having a migration history contribute to increased heat exposure. These factors also influence people's capacity to implement behavioural as well as structural adaptation measures to protect their health from heat."
Dr. Franziska Matthies-Wiesler, researcher at the Institute of Epidemiology at Helmholtz Munich and at the Centre for Planetary Health Policy (CPHP)
We Breathe Climate Change: Information Graphics
Further reading
Not everyone is equally affected by extreme heat. People with lower incomes, less education, or poor housing are often exposed to more heat and have fewer resources to protect themselves. The study highlights the urgent need to support vulnerable individuals and communities through fairer climate and health and heat health protection and adaptation policies.
Slesinksi et al., 2025: Social inequalities in exposure to heat stress and related adaptive capacity: a systematic review. Environmental Research Letters. DOI: 10.1088/1748-9326/adb509
Sudden cold spells during otherwise warm seasons can significantly increase the risk of stroke. The study emphasizes the importance of early warnings and targeted prevention strategies, particularly for older adults and those with pre-existing health conditions.
He et al., 2025: Stroke risk associated with cold spells occurring during the warm season. Environment International. DOI: 10.1016/j.envint.2025.109514
The study found that high nighttime temperatures are linked to an increased risk of both overall and ischemic stroke. Unlike daytime heat, which is more noticeable, warm nights may go unnoticed – yet they can disrupt sleep and strain the body. The findings highlight the need for better heat protection strategies that also consider temperature during the night.
Read article
Cheng He et al., 2024: Nocturnal heat exposure and stroke risk. European Heart Journal. DOI: 10.1093/eurheartj/ehae277
This article outlines practical proposals for how the healthcare system can better respond to rising heat stress. The authors call for heat protection to become a standard part of healthcare planning – across hospitals, clinics, and public health services.
Boese-O’Reilly et al., 2024: Vorschläge zur Vermeidung gesundheitlicher Folgen von Hitzebelastung als Querschnittsaufgabe im Gesundheitswesen [Proposals for the Prevention Health Consequences of Heat Stress as a Cross-sectional Task in the Health Care System]. Gesundheitswesen. DOI: 10.1055/a-2388-5663
Both low and high temperatures are linked to a higher risk of cardiovascular events. The study highlights a U-shaped relationship between temperature and heart health – suggesting that extremes on either end can strain the cardiovascular system. The findings underscore the importance of protecting at-risk populations during both heatwaves and cold spells.
Ni et al., 2025: Low and high air temperature and cardiovascular risk. Atherosclerosis. DOI: 10.1016/j.atherosclerosis.2025.119238 (in press)
The Lancet Countdown highlights urgent steps Germany must take to protect health amid climate change. The report emphasizes the need for stronger heat protection, cleaner air, and equitable healthcare responses to reduce climate-related health risks. It serves as a call to policymakers to accelerate climate and health measures for a safer future.
Von der Haar et al., 2024: The Lancet Countdown on Health and Climate Change, Policy Brief for Germany 2024
Sudden changes in temperature – both rises and drops – increase the risk of heart attacks. A nationwide study from Sweden found that short-term temperature variability leads to more hospital admissions, regardless of heart attack type. The findings highlight health risks linked to increasing weather variability.
Ni et al., 2025: Short-term exposure to ambient temperature variability and myocardial infarction hospital admissions: A Nationwide Study in Sweden. PLOS Medicine. DOI: 10.1371/journal.pmed.1004607
The platform Hitzeservice.de offers a range of communication materials to raise awareness of heat-related health risks. The collection, first published in 2023, now includes tailored guides for groups such as people with disabilities and on women’s health – supporting inclusive and effective heat protection.
Explore materials on Hitzeservice.de
Estimating the excess mortality attributable to heat is a central element of the documentation of the consequences of climate change for human health. Until now, estimates of heat- related deaths in Germany by the Robert Koch Institute (RKI) have been based on weekly mortality records. This study is the first to use higher resolution data—i.e. daily all-cause mortality linked to daily mean temperatures—from each of the German federal states to assess the heat-related mortality from 2000 to 2023 in Germany.
Huber V, Breitner-Busch S, He C, Matthies-Wiesler F, Peters A, Schneider A: Heat-related mortality in the extreme summer of 2022—an analysis based on daily data. Dtsch Arztebl Int 2024; 121: 79–85. DOI: 10.3238/arztebl.m2023.0254
As global temperatures rise, extreme heat events are projected to become more frequent and intense. Extreme heat causes a wide range of health effects, including an overall increase in morbidity and mortality. It is important to note that while there is sufficient epidemiological evidence for heat-related increases in all-cause mortality, evidence on the association between heat and cause-specific deaths such as cardiovascular disease (CVD) mortality (and its more specific causes) is limited, with inconsistent findings. Existing systematic reviews and meta-analyses of epidemiological studies on heat and CVD mortality have summarized the available evidence. However, the target audience of such reviews is mainly limited to the specific field of environmental epidemiology. This overarching perspective aims to provide health professionals with a comprehensive overview of recent epidemiological evidence of how extreme heat is associated with CVD mortality.
Nidhi Singh, Ashtyn Tracy Areal, Susanne Breitner, Siqi Zhang, Stefan Agewall, Tamara Schikowski and Alexandra Schneider: Heat and Cardiovascular Mortality: An Epidemiological Perspective. 25 Apr 2024, Circulation Research. 2024;134:1098–1112
In June 2019 a consortium of researchers from different disciplines and ten European countries began a journey together in the Horizon2020 climate change and health project EXHAUSTION. The starting point was how the effects of heatwaves, air pollution and a changing climate leads to more heart and lung diseases in Europe, and premature deaths related to these challenges. The aim of the project has been to identify adaptation strategies that will help avoid premature death and disease among vulnerable groups. This includes older people, the chronically ill, and disadvantaged people. The overall goal was to increase European resilience.
As part of the legacy of the project we have developed a white paper including five stand alone chapters which reflects a selection of important findings and results from the project related to the questions above. The paper includes key research and policy recommendations.
Gunnell E. Sandanger et. al: The Exhaustion Project.
Lower air temperatures and cold spells have been linked to higher disease risk, but their short-term impact on myocardial infarction (MI) is not fully understood. This study aimed to examine how these conditions affect MI hospitalization in Sweden. Findings show an increased risk of MI hospitalization 2 to 6 days after exposure to lower temperatures and cold spells.
Ni, W, Stafoggia, M, Zhang, S. et al. Short-Term Effects of Lower Air Temperature and Cold Spells on Myocardial Infarction Hospitalizations in Sweden. JACC. 2024 Sep, 84 (13) 1149–1159. DOI: /10.1016/j.jacc.2024.07.006
Individuals with chronic pulmonary diseases are particularly affected when high temperatures coincide with high levels of air pollution. Heat-related lung problems, such as increased pulmonary load through heat-related hyperventilation together with increased air pollution as well as effects associated with cardiac impairment and pneumonia increase the risk of morbidity and mortality for affected patients during heat waves.
Matthies-Wiesler, N. Nidens, S. Karrasch & A. Schneider: Zeitschrift für Pneumologie Volume 20, March 2023, p. 133-143.
During heat waves, the risk for kidney-related morbidity and mortality increases. Acute kidney injuries, urolithiasis, electrolyte imbalances and urinary tract infections particularly occur. Chronic kidney diseases are also discussed as a possible consequence of climate change. The combination of heat, air pollutants and other environmental factors represents a particular burden for patients with kidney diseases.
N. Nidens et. al: Climate Change up Close: Heat Waves Implications and Prevention, 13. June 2023, Die Nephrologie, p. 203-212.
