Lots of heat waves and cold snaps can increase mortality rates, according to a new study from Harvard T.H. Chan School of Public Health.
Previous studies have shown that more people die when it gets very hot or very cold. But those studies looked only at short-term death rates, so don’t shed light on the long-term effect of temperature on people’s life expectancy. The new study, published July 13, 2015 in Nature Climate Change, charted temperature and death rates among New England’s Medicare population—nearly 3 million people—zip code by zip code, from 2000-2008. The authors found that the more the weather varied from the norm, whether within a season or from year to year, death rates increased.
“People do not adapt well to changes in temperature,” senior author Joel Schwartz, professor of environmental health, said in a July 13, 2015 interview on WBUR’s CommonHealth. He noted that temperature can affect blood pressure, lung function, and increase heart attack risk.
“If the climate keeps bouncing around, going from 90 one day to 70 and then back up to 87—that is what puts the most stress on people’s bodies because they just don’t have time to adapt to the new temperature before it changes again,” Schwartz said. He said it’s important to better understand how climate change will impact temperature variability to assess the potential human health impacts.