More exercise equals less disease

The benefits of physical activity on reducing risk of chronic diseases are well documented. Relatively few studies, however, have quantified the upper limit of exercise for which there is significant chronic disease risk reduction. To see health benefits, the World Health Organization (WHO) recommends people get at least 600 metabolic equivalent (MET) minutes of total activity per week, which translates to around 150 minutes of brisk walking or 75 minutes of running per week. There’s varying evidence as to how much chronic disease risk reduces with different levels of increase in total exercise levels. Researchers aimed to quantify the dose-response relationship between total physical activity levels and five disease outcomes.

The five disease outcomes assessed in this meta-analysis were breast cancer, colon cancer, diabetes, ischaemic heart disease and ischaemic stroke. Physical activity levels across different domains of life were included and standardised to a consistent total level, measured in total MET minutes of activity per week. The domains included physical activity completed in leisure time, at work, as methods of transportation, and at other points in daily life.

After analysing a large number of studies, researchers found that higher levels of total physical activity were associated with lower risk of all disease outcomes. Increases from 600 MET minutes/week to 3000-4000 MET minutes/week produced substantial risk reduction. The decrease in risk associated with exercise levels higher than 3000-4000 MET minutes/week was minimal.

Implications

The results from this meta-analysis suggest that people can reap substantial benefit from undertaking far more than the minimal recommended activity levels of 600 MET minutes/week. People, and particularly those with other risk factors for chronic conditions, may benefit from increasing their activity levels to 3000-4000 MET minutes/week.

References

Kyu, H et al. (2016). Physical activity and risk of breast cancer, colon cancer, diabetes, ischemic heart disease, and ischemic stroke events: systematic review and dose-response meta-analysis for the Global Burden of Disease Study 2013. BMJ; 354: i3857 http://dx.doi.org/10.1136/bmj.i3857.