Heat and inactivity could claim thousands of Indian lives by 2050: Study

Rising temperatures driven by climate change could push millions more adults into physical inactivity by 2050, potentially contributing to hundreds of thousands of premature deaths worldwide and billions of dollars in lost productivity, according to a modelling study published in the journal The Lancet Global Health.

The analysis warns that extreme heat may increasingly limit how often people exercise or engage in routine movement, adding a new dimension to the global health burden of inactivity.

Physical inactivity is already one of the leading behavioural risk factors for chronic disease, with about one in three adults worldwide failing to meet recommended exercise levels set by the World Health Organisation (WHO).

Researchers examined data from 156 countries between 2000 and 2022 to estimate how rising temperatures might influence physical activity patterns through 2050.

Their model suggests that for every additional month in a year when the average temperature exceeds 27.8°C, the prevalence of physical inactivity could rise by about 1.5 percentage points globally.

The effect is expected to be stronger in low- and middle-income countries, where inactivity could increase by around 1.85 percentage points for each such month, while high-income countries showed no clear trend.

Globally, this shift could translate into roughly 470,000 to 700,000 additional premature deaths each year and productivity losses estimated at $ 2.4–3.7 billion annually.

For India, the projections are particularly concerning. The study estimates that about 10.2 deaths per lakh could eventually be linked to heat-driven physical inactivity.

With the country already experiencing longer and more intense heatwaves, the findings point to a potential public health challenge that extends beyond heatstroke and dehydration.

Recent research suggests that the baseline problem is already substantial. A 2024 analysis published in The Lancet Global Health found that nearly half of Indian adults do not meet recommended activity levels. Physical inactivity in India has climbed sharply- from 22.4 percent in 2000 to 45.4 percent in 2022- and could reach 55% by



2030 if current trends continue.

The problem is also unevenly distributed, with significantly higher inactivity among women (52.6 percent) compared with men (38.4percent).

Public health researchers say these patterns matter because sustained physical activity plays a crucial role in preventing chronic diseases such as heart disease, diabetes and certain cancers.

Shifalika Goenka, a researcher studying physical activity and chronic diseases at the Centers for Disease Control and Prevention (CCDC), noted that emerging evidence shows both higher overall activity levels and consistent exercise over time are linked to lower risks of major chronic illnesses.

Earlier this year, a landmark study had said that walking at an average pace for just five additional minutes a day was linked to a 10 percent reduction in deaths among moderately active adults, and a 6 percent reduction among the least active.

The new model, meanwhile, also predicts that the sharpest increases in inactivity may occur in already hot regions such as Central America, the Caribbean, eastern Sub-Saharan Africa and equatorial Southeast Asia, where inactivity could rise by more than four percentage points for every additional month above the 27.8°C threshold.

However, the authors caution that these projections come with uncertainties.

The model relies largely on self-reported physical activity surveys and focuses primarily on temperature changes, without fully accounting for factors such as urban design, cultural habits or adaptation strategies that could influence behaviour.

Even so, the findings highlight the need for proactive planning as global temperatures continue to climb.

Researchers suggest measures such as designing cooler urban environments with shade and green spaces, ensuring access to affordable air-conditioned public facilities where people can exercise safely, and providing clear guidance on physical activity during extreme heat.

Ultimately, they argue, reducing greenhouse gas emissions remains central to limiting long-term health risks linked to rising temperatures- including the quieter but significant threat of inactivity.