The Effect of Sedentary Behaviour on Healthy Ageing

Introduction

Healthy ageing is a significant public health issue as the global population ages. Currently, 8.5% of the world’s population is aged 65 or older, and this figure is expected to rise to 20% by 2050. Ageing often brings various health challenges, including chronic diseases, cognitive decline, psychological disorders, and physical function limitations. These issues impose a substantial burden on individuals, families, and society. Healthy ageing, defined as being disease-free and maintaining physical, mental, and cognitive health, is achieved by only 10% to 35% of older adults. Identifying modifiable factors can inform interventions to promote healthy ageing. A recent study explored the impact of sedentary behaviour (SB) and light physical activity (LPA) on healthy ageing.

Sedentary Behaviour and Its Implications

Sedentary behaviour, particularly prolonged television watching, is significantly associated with lower odds of healthy ageing. Modern society has seen an increase in SB, which now occupies approximately 60% of adults’ waking time. This is concerning as prolonged sitting has been linked to various health issues, including chronic diseases and mortality. Watching television, in particular, has been identified as the strongest negative risk factor among several types of SB.

Prolonged sitting affects physical function by causing cellular and molecular responses in skeletal muscles, impairing their function and mitochondrial activity. This, in turn, affects glucose homeostasis, insulin sensitivity, and lipid metabolism, contributing to chronic diseases. Furthermore, prolonged sitting impacts vascular markers, such as cerebral blood flow, which may explain the association between television watching and various domains of healthy ageing.

The Role of Light Physical Activity

Light physical activity, both at home and at work, has been associated with higher odds of healthy ageing. Unlike moderate-to-vigorous physical activity (MVPA), which accounts for only 4% of adults’ waking time, LPA is more feasible for older adults who may have limited physical ability. Activities such as housework, gardening, and walking around the home or workplace contribute significantly to overall energy expenditure and are linked to better health outcomes.

Replacing sedentary behaviour with LPA can promote healthy ageing. For instance, substituting television watching with LPA or even sleep (in individuals who sleep 7 hours per day) is associated with increased odds of healthy ageing. This finding is crucial as it suggests that even low-intensity activities can have a substantial impact on health.

The Benefits of Moderate-to-Vigorous Physical Activity

Moderate-to-vigorous physical activity is associated with even higher odds of achieving healthy ageing compared to LPA. Engaging in MVPA, such as running or weight training, has been shown to reduce the risk of mortality and improve various health outcomes. However, older adults often find it challenging to engage in high-intensity activities due to physical limitations.

This study found that replacing sedentary behaviour with MVPA leads to stronger associations with healthy ageing. This demonstrates the importance of promoting physical activity, regardless of its intensity, to improve health outcomes in older adults. Public health campaigns should focus on increasing physical activity levels while reducing sedentary behaviours, particularly prolonged television watching.

Public Health Implications and Recommendations

Given the strong association between sedentary behaviour and healthy ageing, public health initiatives should aim to reduce SB and promote physical activity. In the United States, 84% of older adults spend 2 or more hours per day watching television, and 25.7% report sitting for more than 8 hours per day. These statistics highlight the need for targeted interventions to reduce sedentary time and encourage more active lifestyles.

Physical activity includes both non-exercise activities (e.g., housework and gardening) and exercise activities (e.g., running and weight training). Non-exercise activities contribute significantly to overall energy expenditure and should be promoted as viable options for older adults. Substituting sedentary behaviour with even light physical activities can lead to meaningful improvements in health outcomes.

Conclusion

In conclusion, sedentary behaviour, especially prolonged television watching, is associated with decreased odds of healthy ageing. In contrast, light physical activity and moderate-to-vigorous physical activity are linked to significantly increased odds of achieving healthy ageing. Replacing sedentary behaviour with physical activity, regardless of its intensity, can promote healthy ageing and improve overall health outcomes. These findings provide essential evidence for promoting active lifestyles and reducing sedentary behaviours to achieve optimal health in older adults.