A new study warns that escalating global temperatures may significantly increase physical inactivity, particularly in lower-income regions, potentially contributing to hundreds of thousands of premature deaths each year by 2050.
Researchers analysed data from 156 countries spanning 2000 to 2022 to model the impact of rising temperatures on global activity levels. They found that each additional month with an average temperature above 27.8°C corresponded to a 1.5 percentage point rise in inactivity worldwide. In low- and middle-income countries, the effect was stronger, with inactivity climbing 1.85 points per month.
The study, published in The Lancet Global Health, highlighted the physiological effects of extreme heat, noting that higher temperatures increase cardiovascular strain, dehydration risk, and perceived exertion. “Physical inactivity is already a major risk factor for cardiovascular disease, type 2 diabetes, certain cancers, and mental health conditions, all of which can reduce life expectancy,” said Christian García-Witulski, the study’s lead author.
Inactivity already accounts for roughly 5 percent of adult deaths globally, and about one-third of adults worldwide fail to meet World Health Organization (WHO) physical activity guidelines, which recommend 150 minutes of moderate or 75 minutes of vigorous activity per week. The study projects that rising inactivity linked to heat could result in nearly 500,000 additional premature deaths annually by 2050, alongside productivity losses estimated between $2.4 billion and $3.68 billion (€2.18 billion to €3.35 billion).
Regions already experiencing high temperatures are likely to be hit hardest. Central America, the Caribbean, eastern sub-Saharan Africa, and equatorial Southeast Asia could see monthly inactivity rise by more than four percentage points. Women and adolescents may be particularly affected, as access to climate-controlled recreational spaces is often limited and public health budgets in these regions are insufficient to address the health consequences.
The study calls for public health strategies that treat physical activity as a climate-sensitive issue rather than solely an individual lifestyle choice. Urban planning can play a crucial role, with measures such as connected shade networks, reflective surfaces, water features, and climate-sheltered public spaces supporting safer outdoor activity while also preserving cognitive performance and protecting labour productivity.
Evidence continues to show that staying active can substantially reduce mortality risk. Research published last year in The Lancet Public Health found that adults who shift from inactive to active lifestyles lower their risk of death by 22 percent. Achieving just 7,000 steps a day has been linked to reduced risks of dementia, heart disease, depression, type 2 diabetes, and certain cancers, with risk reductions ranging from 6 percent for cancer to 38 percent for dementia.
As global temperatures rise, experts warn that without interventions to encourage safe physical activity, the health impacts of inactivity could become a major, climate-driven public health crisis, particularly in regions already facing extreme heat.
