Key words: Epidemiology, Health, Physical activity

Why is this study important?

Physical activity is known to help prevent early death.1 Current guidelines recommend 150-300 weekly minutes of moderate-intensity physical activity, or 75-150 weekly minutes of vigorous-intensity activity, or a combination of both, to achieve health benefits.2 However, most research on physical activity that supported the development of these recommendations were based studies that assessed physical activity on one-time-point. Evidence has suggested that people’s activity levels can change as they go through different life stages (e.g., from middle to older age) or major life events, like illness or retirement.3 Therefore, studies that rely on a single measurement may fail to capture how changes in physical activity affect health, making their findings less applicable for people with varying activity levels.

We conducted this study to identify general patterns of physical activity across adulthood and examine how different patterns (or cumulative amount) of physical activity relate to the risk of early death from all cause, cardiovascular disease (CVD), and cancer.4 

How did the study go about this?

We conducted a systematic review and meta-analysis of 85 observational studies, with sample sizes ranging from 357 to 6,572,984 participants. All the studies measured physical activity in at least two time points, with their associations with death from all causes, cardiovascular disease, or cancer. We identified three main ways to model physical activity over time:

• Activity trajectory – illustrated how activity levels change over time
• Time-varying activity – measured people’s activity levels repeatedly, and accounted for the variance in analysis  
• Average/cumulative activity – represented the total amount of activity over time

For each of these approaches, we synthesised the associations between physical activity and different causes of death. As the studies measured physical activity in different ways, we converted all activity levels into MET-hours/week so they could be directly compared across studies. Using this harmonised data, we then synthesised the relationships between different doses of physical activity and the risk of death.

What did the study find?

(1) The relationship between long-term physical activity and the risk of death can vary depending on a person’s activity pattern. Specifically:  

• People who remained consistently active over time had about a 30–40% lower risk of death from any cause, while those who became active had about a 20–25% lower risk.
• People who decreased their activity levels had much less risk reduction in all-cause death compared to those who were consistently active or became active.
• Similar trends were also observed for death from CVD, while the findings were less robust for death from cancer.  

(2) The relationship between long-term physical activity and the risk of all-cause death can vary depending on physical activity levels.  

• For people who were either consistently active or became active, the greatest drop in risk occurred below the recommended weekly amounts. However, activity levels above the recommendation offered only limited extra benefit, especially for those increasing their activity over time.
• People who became inactive might still have a lower risk of death compared to those who were always inactive. But this seemed to depend on how active they were before, and more research is needed. 

What are the key take-home points?

• Staying physically active throughout adulthood is associated with a lower risk of death from any cause, including death from heart disease.
• People who are not active in early adulthood but start exercising later may still have significant health benefits. 
• It is never too late to start being physically active. Starting at any point in adulthood can lead to a longer and healthier life. 

Blog Authors: Ruyi Yu, Gregore I Mielke, Stephanie L Duncombe, Hsin-Fang Chung      

The University of Queensland, School of Public Health, QLD, Australia

Reference  

1. Garcia L, Pearce M, Abbas A, et al. Non-occupational physical activity and risk of cardiovascular disease, cancer and mortality outcomes: a dose-response meta-analysis of large prospective studies. Br J Sports Med 2023;57(15):979-89. doi: 10.1136/bjsports-2022-105669 [published Online First: 20230228]
2. World Health Organization (WHO). WHO guidelines on physical activity and sedentary behavior 2020 [Available from: https://www.who.int/publications/i/item/9789240015128.
3. Gropper H, John JM, Sudeck G, Thiel A. The impact of life events and transitions on physical activity: A scoping review. PLoS One 2020;15(6):e0234794. doi: 10.1371/journal.pone.0234794 [published Online First: 20200622]
4. Yu R, Duncombe SL, Nemoto Y, et al. Physical activity trajectories and accumulation over adulthood and their associations with all-cause and cause-specific mortality: a systematic review and meta-analysis. Br J Sports Med 2025 doi: 10.1136/bjsports-2024-109122 [published Online First: 20250710]