Just a two day “heat wave” may increase the risk of premature heart-related death.
Researchers found that a heat wave – the hottest one percent of temperatures – for two or more days led to increased cardiovascular death risks. The scientists compared heart-related deaths and daily temperatures in Brisbane, Australia, over an eight-year period.
The average daily temperature in Brisbane is about 69 degrees. Heat waves in this study were defined as two or more days at 85 degrees or hotter.
Researchers say extreme temperatures can trigger changes in blood pressure, blood thickness, cholesterol and heart rate. They said the increased death rate might be because people become exhausted due to the sustained strain on their cardiovascular systems without relief, or because health systems become overburdened.
Cold spells – the coolest one percent of temperatures – were also linked with increased deaths, but not as high as during heat. Cold effects lasted longer than heat effects, with the peak in cold effects coming two days after the temperature drop.
Spending a few hours daily in a temperate environment can help reduce heat- and cold-related illnesses and deaths.