[Sportschosun Reporter Jang Jong-ho] It is well known that physical activity helps prevent dementia.
However, a new study has found that the effect can vary greatly depending on the situation in which the body is being used.
Leisure-time exercise such as running, swimming, or cycling has been linked to a lower risk of dementia. By contrast, physical activity at work, such as lifting heavy objects or using the body for long hours in construction or scaffolding jobs, was associated with a higher risk.
Researchers at the University of Southern California (USC) conducted a meta-analysis of 80 studies involving 5,013,910 middle-aged and older adults. They examined how dementia risk changed depending on the setting in which physical activity took place, including work, leisure, housework, and commuting.
The analysis showed that people who were more physically active during their leisure time had a 24% lower risk of dementia than the least active group.
On the other hand, people with high levels of occupational physical activity had about a 20% higher risk of dementia than those with lower levels.
The study is drawing attention because it systematically examined the so-called Physical activity paradox in relation to dementia.
In general, physical activity is known to reduce the risk of chronic diseases such as cardiovascular disease and diabetes, while also benefiting brain health. However, previous studies have suggested that people who are physically active for long periods through their jobs may not receive the same health benefits as those who exercise during their free time.
The researchers explained that occupational physical activity and leisure-time exercise are similar only in the sense that both involve moving the body. In reality, the environments are very different.
Leisure-time exercise can be adjusted to match a person's fitness level and circumstances. It is also often accompanied by enjoyment, social interaction, and stress relief. Manual labor, by contrast, often involves repeating the same motions for long periods or standing for extended hours. In many cases, workers must also lift heavy objects or work with limited rest time.
In physically demanding jobs such as construction, manufacturing, and logistics, workers are also more likely to be exposed to noise, air pollution, and occupational stress. Long or irregular working hours may leave little time for exercise after work.
The researchers stressed that the link between occupational physical activity and dementia risk cannot simply be explained by the fact that people are moving more. They said a range of factors, including working conditions, socioeconomic status, stress, and recovery time, may have played a role.
However, because the study combined existing observational research, it does not prove that manual labor directly causes dementia.
Another limitation is that most of the studies measured physical activity through self-reports from participants.
The researchers said more studies are needed in the future to objectively measure not only the intensity and duration of physical activity, but also the work environment and recovery time.
The paper was recently published in The Lancet Public Health.
Jang Jong-ho bellho@sportschosun.com
This article has been translated by GripLabs Mingo AI.
