Eleven-minutes of brisk walk a day shown to reduce risk of early death

Current guideline recommends at least a 150 min of moderate intensity activity a week (e.g., brisk walking, cycling or playing tennis) or 75 min of vigorous intensity activity a week, spread over 4–5 days a week to reduce risks of cardiovascular disease (CVD). Despite this modest recommendation, uptake for this level of activity remains low in the general population due to time commitments. A new study, published in the British Journal of Sports Medicine conducted by researchers from the MRC Epidemiology Unit at the University of Cambridge has set out to explore the amount of physical activity necessary to have a beneficial impact on several chronic diseases and premature death. One of the main aim is to understand the shape of the dose–response association between levels of physical activity with premature death and chronic disease outcomes.

To do this, researchers performed a systematic review and meta-analysis of 196 peer-reviewed articles, covering more than 30 million participants, from 94 large study cohorts. This, according to the investigators enabled them to produce the largest analysis to date of the association between physical activity levels and risk of heart disease, cancer, and early death.

From their analyses, they concluded that, apart from work-related physical activity, 2 in 3 people reported activity levels below 150 min per week of moderate-intensity activity, and fewer than 1 in 10 managed more than 300 min per week. Overall, higher activity levels of physical activities were associated with lower risks of all outcomes. Compared with inactive individuals, adults who achieved the 150 min of moderate-intensity activity had a 31% lower risk of all-cause mortality, a 29% lower risk of CVD mortality, and a 15% lower risk of cancer mortality. If all individuals accumulated at least 150 min a week, then 15.7%, 12.3%, and 7.1% of all-cause, CVD-related, and cancer-related deaths, respectively, would ‘potentially have been averted’. The researchers also calculated that if everyone in the studies had done the equivalent of at least 150 min per week of moderate-intensity activity, around 1 in 6 (15.7%) premature deaths, 1 in 9 (10.9%) cases of CVD, and 1 in 20 (5.2%) cases of cancer, would have been prevented.

They also found that ‘beyond’ 150 min per week of moderate-intensity activity, the additional benefits in terms of reduced risk of disease or early death were ‘marginal’. Importantly, even reducing the amount of physical activity by half also came with significant benefits. Accumulating 75 min per week of moderate-intensity activity brought with it a 23% lower risk of early death. If everyone managed at least 75 min per week of moderate-intensity physical activity, around 1 in 10 (10%) premature deaths, 1 in 20 (5%) cases of CVD, and nearly 1 in 30 (3%) cases of cancer, would be prevented. Seventy-five minutes per week of moderate activity was also enough to reduce the risk of developing CVD by 17% and cancer by 7%.

The study therefore suggests that doing some level of activity is better than doing none. This is particularly so for individuals who struggles to do the recommended 150 min of moderate-intensity physical activity a week. Thus, ‘11 min a day—75 min a week—of moderate-intensity physical activity—such as a brisk walk—would be sufficient to lower the risk of diseases such as heart disease, stroke, and a number of cancers’, according to the authors.