Inactivity in a warming world could increase premature deaths by 2050

A Lancet Global Health study reports that hotter months are linked to higher physical inactivity and estimates about 470,000–520,000 additional deaths worldwide by 2050; the projections include uncertainty.

A new study published in Lancet Global Health models how rising temperatures are affecting physical activity around the world. The authors used survey and temperature data from 156 countries covering 2000–2022 to estimate links between hotter months and inactivity. They report that each additional month with an average temperature above 82 degrees Fahrenheit was associated with a rise in physical inactivity. The researchers projected that higher inactivity tied to warming could correspond to hundreds of thousands of additional deaths and measurable economic losses by 2050, while noting important uncertainties in the estimates. Key findings: - The study combined national physical activity surveys and temperature records for 156 countries from 2000 to 2022. - Each extra month averaging above 82°F was associated with about a 1.4 percentage point increase in physical inactivity globally. - The authors estimate roughly 470,000 to 520,000 additional deaths and $2.4 billion to $2.59 billion in annual productivity losses by 2050 under the modeled scenarios. - The projected increases in inactivity were concentrated in low- and middle-income countries, and the study found a larger estimated rise in inactivity for women than for men. Summary: The study presents modeled evidence that rising temperatures are associated with increased physical inactivity and projects substantial additional deaths and economic impacts by 2050, with most effects forecast in lower-income countries. The estimates are subject to limitations and uncertainty, including reliance on self-reported activity and national average temperatures. Undetermined at this time.