High temperatures driven by climate change could push millions worldwide into physical inactivity by 2050, leading to up to 7,00,000 additional premature deaths every year and about USD 3.68 billion in annual productivity losses, a new study in The Lancet Global Health has warned. The modelling study, led by researchers from Latin America including the Pontifical Catholic University of Argentina, suggests that rising heat alone could erode a substantial share of the World Health Organization’s target of cutting global physical inactivity by 15 per cent by 2030.
The analysis links hotter conditions directly to lower levels of exercise, highlighting climate change as an emerging driver of sedentary behaviour and its associated disease burden. Researchers examined data from 156 countries from 2000 to 2022 to project how temperature increases may shape physical activity patterns through to 2050 under three scenarios: low emissions, continuation of historical trends and rapid fossil fuel-driven development. The study estimates that by 2050, each additional month with an average temperature above 27.8 degrees Celsius would raise physical inactivity by 1.5 percentage points globally and by 1.85 percentage points in low and middle income countries.
“By 2050, these increases translate into an additional 0.47–0.70 million deaths and Intl$ 2.40–3.68 billion in annual productivity losses,” the authors wrote, underscoring the economic as well as health implications of a climate-linked shift away from regular movement. They warn that the consequences will be felt most acutely in tropical regions, where heat and humidity are already high and large populations live in low-resource settings.
India is among the countries expected to see a measurable health impact, with the study projecting a mortality rate attributable to physical inactivity of 10.62 deaths per 1,00,000 population by 2050 under all three future scenarios assessed. The authors note that physical inactivity is already a major global health problem, with about one in three adults failing to meet WHO-recommended levels of weekly exercise. Current WHO guidance advises adults aged 18 to 64 years to undertake at least 150 minutes of moderate intensity or 75 minutes of vigorous intensity physical activity each week, along with muscle-strengthening activities involving major muscle groups on two or more days.
Climate change is now making it harder to achieve those benchmarks, the study suggests. Separate research published recently in the journal Environmental Research Health has shown that in some tropical and subtropical regions, hot and humid conditions during the hottest hours of the year restrict safe physical activity for both younger and older adults to largely sedentary behaviours such as sitting and lying down. The Lancet Global Health paper argues that as the planet warms, these constraints will become more frequent and severe, further curtailing opportunities for safe outdoor exercise.
“Rising temperatures are projected to increase the prevalence of physical inactivity, translating into additional premature deaths and productivity losses, especially in tropical regions,” the researchers said, calling the implications for global health “immediate”. They argue that public health planning has yet to fully account for heat as a barrier to physical activity, even as governments and health systems encourage people to move more to prevent non-communicable diseases.
In response, the authors outline a set of cost-effective measures that could buffer populations against a “heat-driven sedentary transition”. These include integrating clear heat-risk messages into exercise guidelines, directing climate finance towards shade-rich active transport corridors, subsidising cooled exercise facilities for at-risk groups and enforcing robust occupational heat safety standards. Such interventions, they contend, would deliver concurrent benefits for public health, urban liveability and emissions reduction.
The study concludes that physical activity can no longer be treated as a discretionary lifestyle choice in policy terms but must be recognised as a climate-sensitive necessity. Without proactive measures to adapt cities, workplaces and health advice to a hotter world, the authors warn of a rising burden of cardiometabolic diseases and mounting economic losses tied to inactivity in the decades ahead.
