The influence of climate change on human cardiovascular function.

Climate change is considered to have great impact on human health. The heat waves have been associated with excess morbidity and mortality of cardiovascular diseases (CVD) across various populations and geographic locations. Important role in the heat-induced cardiovascular damage has endothelial dysfunction. It has been noticed that hot weather can impair tone and structure of the blood vessels via interfering with variety of biological factors such as nitric oxide synthesize, cytokine production and systemic inflammation. Also, due to dehydration and increased blood viscosity, by promoting thrombogenesis, heat has important impact on patients with atherosclerosis. During chronic exposure to the cold or hot weather cardiovascular function can be decreased, leading to a higher risk of developing heart attack, malignant cardiac arrhythmias, thromboembolic diseases and heat-induced sepsis like shock. It has been shown that changes in the ambient temperature through increasing blood pressure, blood viscosity, and heart rate, contribute to the cardiovascular mortality. The majority of deaths due to heat waves especially affect individuals with preexisting chronic CVD. This population can experience a decline in the health status, since extreme ambient temperature affects pharmacokinetic parameters of many cardiovascular drugs. Increased mortality from ischemic or hemorrhagic stroke can also be related to extreme temperature variations. On a cellular level, higher ambient temperature can limit storage of ATP and O2increase amount of free radicals and toxic substances and induce neuronal apoptotic signal transduction, which all can lead to a stroke. Preserving cardiovascular function in context of extreme climate changing tends to be particularly challenging.