Investigators found that individuals who engaged in light- and moderate-to-vigorous–intensity physical activity daily had a lower risk of developing cancer compared with those who were more sedentary, according to a recent study published by Shreves et al in the British Journal of Sports Medicine. The findings were among the first to evaluate the cancer risk reduction associated with light-intensity activities such as performing errands or household chores.
Background
The risk of certain types of cancers, such as breast cancer and colorectal cancer, have been linked to physical activity habits.
Although previous studies have shown an inverse association between physical activity and cancer risk, most of these studies relied on self-reported questionnaires—which may not accurately capture the intensity of different activities. Earlier studies that used objective measures were also focused on higher-intensity physical activity.
Study Methods and Results
In the prospective cohort study, the investigators examined the outcomes of over 85,000 adults with a median age of 63 years residing in the United Kingdom who participated in the UK Biobank. The participants wore wrist accelerometers that tracked their total daily activity, activity intensity, and daily step count over a period of 1 week. The investigators then assessed the relationship between the daily averages and the incidence of 13 cancer types—including breast cancer and colorectal cancer.
After a mean follow-up of 5.8 years, 2,633 of the participants had been diagnosed with 1 of the 13 cancer types. Those with the highest total amount of daily physical activity had a 26% lower risk of developing cancer compared with those who had the lowest amount of daily physical activity.
The investigators explored the impact of replacing daily sedentary time with light- and moderate-to-vigorous–intensity physical activity and revealed that this shift was associated with a reduced risk of cancer. These associations remained even after adjusting for demographic factors, lifestyle factors, body mass index, and other health conditions.
Further, higher daily step count—but not step intensity—was correlated with a lower risk of cancer. Compared with the cancer risk among the participants taking 5,000 steps per day, the cancer risk was 11% lower among those taking 7,000 steps per day and 16% lower among those taking 9,000 steps per day. Beyond 9,000 steps, the risk reduction plateaued.
The findings suggested that less physically active individuals may lower their cancer risk by incorporating more walking, at any pace, into their daily routine.
Disclosure: For full disclosures of the study authors, visit bjsm.bmj.com.
