As India grapples with intensifying heatwaves, unseasonal rainfall, and cold spells, a new international study has sounded an alarm on a less visible but potentially devastating consequence—a rise in cardiovascular disease among middle-aged and elderly populations.
Published in the American Journal of Preventive Medicine, the study analyzed data from 157 cities in China and establishes a clear association between extreme climate events and increased incidence of heart disease. While the research is geographically centered on China, experts said the findings hold significant implications for India, which is witnessing similar climate volatility coupled with a rapidly aging population.
India is already home to one of the largest burdens of cardiovascular disease globally, accounting for nearly a quarter of all deaths. With climate change accelerating, the intersection of environmental stressors and public health is becoming harder to ignore.
The study highlighted that extreme heat—defined as temperatures exceeding 38°C—has the most pronounced effect on cardiovascular risk. Each additional day of such heat exposure was associated with a measurable increase in heart disease cases.
This is particularly relevant for India, where prolonged heatwaves have become more frequent and intense over the past decade. Northern and central regions routinely record temperatures above 45°C during peak summer months.
While India is often associated with heat, extreme cold also poses risks. The study found that temperatures below -10°C increased cardiovascular disease prevalence, albeit to a lesser extent than heat.
In the Indian context, regions such as North India and the Himalayan belt experience sharp drops in temperature during winter. Cold conditions can constrict blood vessels, elevate blood pressure, and increase blood viscosity, all of which contribute to higher cardiac risk.
One of the more surprising findings of the study is the impact of extreme precipitation. Unlike temperature extremes, heavy rainfall events do not follow predictable geographic patterns but still show a strong link to increased cardiovascular risk at the individual level.
India’s monsoon, increasingly erratic due to climate change, brings intense bursts of rainfall that disrupt daily life, damage infrastructure, and strain healthcare access. Sudden changes in temperature and humidity during such events may trigger cardiovascular stress, particularly in vulnerable populations.
The research identified specific high-risk groups, many of which mirror India’s demographic realities. Pre-retirees, smokers, rural residents, and individuals with limited social support were found to be particularly vulnerable.
Urban-rural disparities also play a role. In India, rural areas often lack robust healthcare infrastructure, making it harder to respond effectively during extreme weather events. Additionally, air pollution—a persistent issue in many Indian cities—may compound the impact of heat and cold on heart health.
Interestingly, the study also noted that body mass index (BMI) interacts differently with temperature extremes. While higher body fat may offer limited protection against extreme heat by acting as insulation, it exacerbates risks during cold exposure due to increased cardiovascular strain.
Public health experts argue that India must integrate climate considerations into its healthcare planning. The study suggests several measures that could be adapted to the Indian context. These include linking weather alerts with healthcare systems to warn high-risk populations in advance.
Also, strengthening primary healthcare networks, especially in rural and climate-vulnerable regions, has been recommended.
Promoting awareness about managing heart health during extreme weather and expanding green spaces in urban areas to mitigate heat island effects can help these vulnerable populations.
There is also a need for better data integration. Tracking climate patterns alongside health outcomes could help policymakers design targeted interventions and allocate resources more effectively, said the study.
"Elderly individuals are particularly vulnerable to extreme weather because their cardiovascular system has a reduced ability to adapt to sudden temperature changes,” explained Dr. Tarun Kumar, Associate Director and Interventional Cardiologist at Medanta-Moolchand Heart Centre, Delhi.
“During heatwaves, the body loses fluids rapidly, leading to dehydration and thicker blood, which can increase the risk of clot formation and heart attacks. On the other hand, extreme cold causes blood vessels to constrict, raising blood pressure and placing additional strain on the heart,” pointed out Dr. Tarun Kumar, who was not part of the study.
He added that existing conditions such as hypertension, diabetes, and coronary artery disease further heighten the risk. “In older adults, even minor environmental stressors can trigger serious cardiac events. This is why preventive care, adequate hydration, temperature control, and timely medical attention are critical during extreme weather conditions.”
He also cautioned that climate change should no longer be viewed solely as an environmental issue. Its health implications—particularly for NCDs like cardiovascular conditions during extreme weather—demand urgent, coordinated action, said Dr. Tarun Kumar.
