Effects of Temperature on Heart Disease
Excess mortality from cardiovascular diseases has been found significantly associated with extremely high temperature. In addition, increased mortality during heat waves has been attributed mainly to cardiovascular conditions and cerebrovascular disorders.
This finding differed from previous studies which suggested that the elderly were more vulnerable to heatwaves than younger people.
Cold temperature could lead to thrombosis, and physical activity during cold weather can increase the risk of stable angina and acute coronary syndrome (Greenberg JH, Bromberg J, 1963). Several studies have also shown that cold temperature increases the risk of CVD events (Rowell LB. Human, 1974). However, the effect of low temperature on CVD admissions found in this study occurs at higher temperature thresholds and are of greater magnitude than the effect found in other studies. This supports the hypothesis that cold effect in a warmer climate, where people usually do not have good houses to protect them from the cold weather, appears to be severe than that in a colder climate. The cold effect found in this study generally occurred 4–15 days following exposure, peaking at a week's delay, and is consistent with the results of delayed cold effect found in other studies ( Ohshige K, Hori Y, Tochikubo O, 2006).The effect of the more extreme temperature (13°C) was more pronounced on CVD admissions than that of less extreme temperature (20°C). The effect of temperature at 25°C on CVD admissions is almost identical to that at 26°C, which is the reference temperature. The effect of temperature of 30°C which is higher than the reference temperature reduced the risk of CVD admissions at lag 0 and increased the risk of CVD admissions from lag 5 to lag 10.
Preventive measures may limit the expected effects of climate change on cardiac health, namely increased patient awareness, social networking, increased access to air-conditioned environments, physician and hospital preparedness and heat-wave alert response systems. Admittedly, such measures are rather limited in their beneficial potential impact. Concerted actions to reduce emissions of greenhouse gases, such as changes in transportation patterns, a lower consumption of meat from cows and sheep and architectural solutions for the over-heating of indoor spaces, will have certain cardiac co-benefits and serve as an opportunity to modify lifestyle habits on a large population scale. Increased access to appropriate health care, particularly in low-income populations, is another important step towards coping better with the cardiac challenges of climate change.
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