Climate-Induced Extreme Weather Events and their Effects on the Pathogenesis of Cardiovascular Diseases
Abstract
Climate change due to anthropogenic greenhouse gas emissions is a developing global health epidemic that becomes more severe, and its consequences are disproportionately borne by vulnerable subpopulations. The most susceptible group of these is the elderly population, which is highly prone to cardiovascular (CV) outcomes of extreme weather conditions such as heatwaves and harsh cold. To devise effective adaptation mechanisms, it is essential to understand the pathogenesis behind the development of the climate-induced CV disease. The main processes connecting severe temperatures with the CV pathology are complicated and many-sided. There are a number of regulatory pathways that are initiated by exposure to non-optimal temperatures. These consist of increased temperature-sympathetic reactivity and cold-activated renin-angiotensin system. Heat exposure may result in dehydration and electrolyte imbalances, and cause systemic inflammatory responses by heat stroke, whereas cold exposure provokes peripheral vasoconstriction, thereby affecting the myocardial oxygen supply-demand relationship. The worsening of risk is also caused by high temperature, which increases the platelet volume and blood viscosity. Furthermore, air pollution caused by climate change is a cofactor, and the delicate particulate matter is associated with pro-arrhythmic effects, e.g., atrial fibrillation, and systemic whole-body inflammation. High mortality and morbidity rates of the elderly in the net clinical outcome include increased incidences of acute myocardial infarction, heart failure (HF), and cardiac arrhythmias. Extreme weather also disrupts animal ecosystems, with heatwaves and cold stress causing mass wildlife mortality, altered migration patterns, and changes in disease-carrying animal behavior. These ecological disturbances reflect the broader biological impact of temperature extremes and reinforce how environmental instability compounds cardiovascular risk in elderly populations. As an example, in literature, the variability of temperature, the extent of which is the diurnal temperature range (DTR), was identified as having a significant impact on HF admission rates in older patients during cold seasons. This residual CV risk needs to be reduced with an urgent requirement for a cross-disciplinary approach that cuts across individual care through systemic interventions in the form of improving early warning mechanisms and policy interventions in health education.