A new study warns that unchecked climate change could lead to 700,000 premature deaths annually by 2050, driven by rising temperatures that make physical activity unsafe. The research, led by scientists in Latin America and published in The Lancet Global Health, analysed data from 156 countries between 2000 and 2022.
The study found that each additional month per year with an average temperature above 27.8°C is projected to increase global physical inactivity by about 1.5%. In low- and middle-income countries, the rise is even steeper at around 1.85%. By 2050, this shift could also result in annual productivity losses of roughly £2.8 billion.
Physical inactivity is already a global problem, with about one in three adults failing to meet weekly exercise targets. Hotter, more humid days make everyday movement such as walking to work or cycling harder and riskier, particularly for those who work long hours, commute on foot, or lack access to air-conditioned facilities.
Tropical regions and lower-income communities are expected to be hit hardest, as heat is most intense and shade, cooling, and safe facilities are scarcer. The authors warn that heat alone could undermine the World Health Organization's goal to reduce global inactivity by 15% by 2030.
Governments are urged to build shaded walking and cycling routes, and subsidise access to air-cooled sports halls and pools for at-risk groups, including older adults and outdoor workers. Lead author Christian García-Witulski said: 'Treating physical activity as a climate-sensitive necessity – rather than a discretionary lifestyle choice – will be essential to prevent a heat-driven sedentary transition.'
