Did you know there is a link between some cancers and a lack of physical activity, including strong evidence of a link with colorectal cancer and premenopausal breast cancer, and some evidence of a link with lung cancer?
Research led by Professor Emmanuel Stamatakis at the University of Sydney has found that doing just 3.5 minutes a day of vigorous intermittent lifestyle physical activity (VILPA) is associated with a 28-29% reduction in the risk for these cancer, while 4.5 minutes of VILPA is linked to an even greater 31-32% decrease in risk.
This could make a real difference for the 70-80% of middle-aged and older adults who either exercise infrequently or not at all in their leisure time.
Vigorous Intermittent Lifestyle Physical Activity and Cancer Incidence Among Nonexercising Adults, 27th July 2023, Emmanuel Stamatakis et al:
https://jamanetwork.com/journals/jamaoncology/fullarticle/2807734
The relationship between physical activity and health is well-documented, with numerous studies highlighting the benefits of regular exercise. However, there is a growing body of evidence suggesting that a lack of physical activity may contribute significantly to the development of various types of cancer. What are the mechanisms behind this connection, and the implications for public health?
Physical Inactivity is a Global Health Concern
Lack of physical exercise is a worldwide problem, with sedentary lifestyles becoming increasingly common due to technological advancements and changes in work environments. The World Health Organisation (WHO) identifies physical inactivity as one of the leading risk factors for global mortality, contributing to numerous chronic health conditions, including cancer.
The Link Between Physical Inactivity and Cancer
The connection between sedentary lifestyles and cancer is complex and multifaceted. Research indicates that regular physical activity can help reduce the risk of several cancers, including colorectal, breast, and lung cancers. Conversely, a sedentary lifestyle may increase the likelihood of developing these cancers. But why exactly is this?
Colorectal Cancer: Colorectal cancer is among the most common cancers worldwide. Studies have consistently shown that physical inactivity is a significant risk factor for this type of cancer. Regular physical activity helps in maintaining a healthy weight, reducing inflammation, and improving gut health, all of which are believed to lower the risk of this type of cancer.
Premenopausal Breast Cancer: The link between physical inactivity and premenopausal breast cancer is particularly concerning. Physical activity has been shown to regulate hormones such as oestrogen and insulin, which play a role in breast cancer development. Inactive lifestyles can lead to obesity, another risk factor for breast cancer, by influencing hormone levels and immune function.
Lung Cancer: Although smoking remains the primary cause of lung cancer, physical inactivity also contributes to its risk. Exercise improves lung function and overall respiratory health, potentially reducing the likelihood of lung cancer.
Biological Mechanisms Behind the Risk
Several biological mechanisms explain how physical inactivity can increase cancer risk:
- Hormonal Changes: Exercise influences the levels of certain hormones, including oestrogen and insulin, which are implicated in cancer development. Regular physical activity helps in maintaining hormonal balance, reducing cancer risk.
- Inflammation: Chronic inflammation is a known risk factor for cancer. Physical activity can reduce inflammation levels in the body, thereby potentially lowering cancer risk.
- Immune System Function: Regular exercise strengthens the immune system, enhancing its ability to detect and eliminate cancer cells.
- Obesity and Fat Metabolism: Physical inactivity often leads to obesity, a significant risk factor for various cancers. Fat cells, particularly those around the abdomen, can produce hormones and growth factors that may encourage cancer growth.
The Impact of Exercise Intensity and Duration
The intensity and duration of physical activity also play a role in cancer prevention. Moderate to vigorous exercise, sustained over time, appears to be more effective in reducing cancer risk than light activity. But as has been shown by the above study, just a small amount of exercise makes a big difference.
Preventative Strategies and Public Health Implications
Recognising the link between physical inactivity and cancer has significant implications for public health policy and individual preventative strategies. Efforts to increase physical activity levels across populations can be an effective strategy in cancer prevention. This includes creating supportive environments for exercise, promoting active transportation, and integrating physical activity into daily routines.
The evidence linking physical inactivity to an increased risk of various cancers is compelling. Regular physical activity emerges not only as a vital component of a healthy lifestyle but also as a key preventative measure against cancer. By understanding and addressing the factors that contribute to physical inactivity, individuals and communities can take proactive steps to reduce their cancer risk and improve overall health outcomes.
