Research published in The Lancet Public Health suggests that people aged 60 and over face health dangers from heat exposure at much lower temperatures than previously understood. The study, led by health academics from Stanford University, found that older adults will disproportionately bear the impact of increasingly frequent and sustained periods of extreme heat globally.
Previous studies may have underestimated the risks for older individuals by applying heat balance thresholds accurate for younger people to all age groups. Older adults are known to be more vulnerable to high temperatures due to factors such as reduced sweating, increased heart strain, and less efficient blood vessel widening.
The study indicates that older adults could be at risk of harmful heat stress at just 1.5C of warming above preindustrial levels, compared to 4C for younger adults. A combination of rising global temperatures and a projected doubling of the world's population aged 60 and over to 2.1 billion by 2050 is expected to lead to more heat-related health problems, particularly in low- and middle-income countries.
The UK Health Security Agency has expressed concerns that high temperatures in Britain during 2026, which included five heatwaves in some areas, are likely to result in the highest annual number of heat-related deaths on record. The four-day heatwave in May and eight-day heatwave in June together caused 2,877 excess deaths, nearly double the 1,504 recorded in summer 2025.