A new study published in The Lancet highlights the growing impact of climate change on global health, showing that rising temperatures may significantly increase levels of physical inactivity worldwide.

The research analysed data from 156 countries between 2000 and 2022, examining how exposure to different temperature ranges influences physical activity patterns in adults.

How Heat Affects Physical Activity

The study found that each additional month with average temperatures above 27.8°C was associated with a measurable increase in physical inactivity.

Specifically:

• Global physical inactivity increased by 1.44 percentage points

• In low- and middle-income countries, the increase was higher at 1.85 percentage points

High temperatures can limit outdoor activity due to:

• Increased cardiovascular strain

• Higher perceived exertion

• Risk of heat-related illnesses

These physiological and environmental barriers reduce opportunities for regular exercise.

Projections for 2050

Using climate models based on different future scenarios, researchers estimated that physical inactivity will continue to rise by 2050:

• 0.98 percentage points under low-emission scenarios

• 1.22 percentage points under moderate scenarios

• 1.75 percentage points under high-emission scenarios

Certain regions, including Central America, sub-Saharan Africa, and Southeast Asia, are expected to experience even higher increases, exceeding 4 percentage points.

Impact on Mortality and Global Health

Physical inactivity is a major risk factor for non-communicable diseases and is linked to approximately 5% of global deaths.

The study estimates that increased inactivity due to rising temperatures could result in:

• 470,000 to 700,000 additional deaths annually by 2050

Reduced physical activity is associated with higher risks of:

• Cardiovascular Disease

• Type 2 Diabetes

• Certain cancers

Economic Burden of Reduced Activity

In addition to health impacts, the study highlights significant economic consequences.

Projected increases in physical inactivity could lead to:

• $2.40 to $3.68 billion in annual productivity losses by 2050

The researchers used a “friction-cost” approach, which estimates economic losses based on reduced workforce productivity.

Why Climate Change Reduces Exercise Opportunities

Rising temperatures are reducing the number of thermally safe hours for outdoor physical activity.

According to broader climate data:

• Populations globally are experiencing more hours of heat stress conditions

• Extreme heat events are becoming more frequent and prolonged

These changes disproportionately affect populations with limited access to:

• Air-conditioned environments

• Safe indoor exercise facilities

Implications for Public Health Policy

The findings suggest that climate change is not only an environmental issue but also a behavioral and public health challenge.

Researchers highlight the need for:

• Heat-adaptive urban planning (green spaces, shaded areas)

• Access to climate-controlled exercise facilities

• Public awareness about safe physical activity during heat

These measures could help mitigate the health risks associated with rising temperatures.

The study provides global evidence that increasing temperatures may reduce physical activity levels, contributing to higher mortality and economic losses. As climate change continues, addressing its impact on everyday health behaviors such as exercise may become an important component of public health strategies.

Reference

1. Omar, M., et al. “Climate Change and Physical Inactivity: Global Implications for Mortality and Economic Burden.” The Lancet Global Health, 2025. https://doi.org/10.1016/S2214-109X(25)00472-3