Alaina Shreves from the University of Oxford and colleagues from the UK and the US conducted a prospective study and found that the overall intensity of physical activity, including low-intensity and regular walking, is associated with a dose-dependent reduction in the risk of developing cancer. The work used data from more than 85,000 people (median age 63) from the UK Biobank repository, who wore accelerometers for a week as part of the study. Machine learning algorithms were used to calculate their overall physical activity, sedentary lifestyle, low-intensity activity, and moderate/high-intensity activity. Cases of 13 common types of cancer were recorded in them over an average of 5.8 years. Statistical processing of the data was performed using Cox proportional hazards models adjusted for demographics, general health, and lifestyle. The results were published in the British Journal of Sports Medicine.
Participants in the highest quintile of physical activity (more than 34.3 microgravity units) were found to have a 26 percent lower risk of developing cancer compared with those in the lowest quintile (less than 21.6 microgravity units). Low-intensity activity was associated with a six percent lower risk, while moderate/vigorous activity was associated with a 13 percent lower risk. The number of steps taken per day was inversely associated with cancer risk in a dose-dependent manner, reaching a plateau at around 9,000 steps per day. There was no significant association between risk and walking intensity.