Heat risk isn’t just about the highs: Large daily temperature swings can harm human health – maps show who is affected most

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Shengjie Liu, USC Dornsife College of Letters, Arts and Sciences and Emily Smith-Greenaway, USC Dornsife College of Letters, Arts and Sciences

(THE CONVERSATION) This summer has shown how quickly high temperatures can pose serious health risks, with record-breaking heat waves claiming thousands of lives around the world.

However, it’s not just high and low temperatures that matter. How many degrees the temperature swings within a day – the daily temperature variation – itself poses health risks.

Studies have found that days with larger than normal temperature swings can increase asthma flare-ups and hospitalizations for respiratory and cardiovascular diseases, leading to an overall higher death rate than normal. One study, based on data from 308 cities from 1972 to 2013,...