UK Biobank Study: Highest Physical Activity Levels Cut Cancer Risk by 26% Across 13 Types

Researchers from the National Cancer Institute and the University of Oxford analyzed data from more than 85,000 UK Biobank participants and found that the highest levels of physical activity were linked to a 26% lower risk of developing 13 types of cancer, the study published March 26, 2025, in the British Journal of Sports Medicine reported. The reduction was observed through objective accelerometer measurements of daily activity, including step counts, with benefits seen from both light and moderate-to-vigorous exercise.

The study analyzed data from 85,394 participants in the UK Biobank, with a median age of 63 years, who wore wrist-based accelerometers for one week to objectively measure daily physical activity, including total movement, intensity, and step counts, according to researchers from the National Cancer Institute (NCI) and the University of Oxford. Over an average follow-up period of 5.8 years, during which 2,633 participants developed cancer, the researchers found that those in the highest category of total daily physical activity had a 26% lower risk of developing 13 types of cancer compared to those with the lowest activity levels, the study published March 26, 2025, in the British Journal of Sports Medicine reported.

Those in the highest category of total daily physical activity had a 26% lower risk of developing 13 types of cancer compared to those with the lowest activity levels, the study published March 26, 2025, in the British Journal of Sports Medicine reported.

The 13 cancer types examined included breast and colorectal cancers, which have been previously linked to physical activity, according to the study titled “Amount and intensity of daily total physical activity, step count and risk of incident cancer in the UK Biobank.” The researchers used Cox regression models adjusted for demographic factors, lifestyle behaviors, body mass index (BMI), and other health conditions to isolate the association between activity levels and cancer risk, the paper stated.

The findings showed that both light-intensity and moderate-to-vigorous physical activities were associated with reduced cancer risk, officials said. Light-intensity activity, such as casual walking, was linked to lower risk, and replacing sedentary time with any level of physical activity contributed to the observed benefits. Sedentary behavior by itself was not directly associated with cancer risk, the study noted.

Step count was also a significant factor. Participants taking approximately 7,000 steps per day had an 11% lower cancer risk compared to those averaging 5,000 steps, while those reaching about 9,000 steps per day experienced a 16% lower risk, according to the researchers. The risk reduction plateaued at around 9,000 steps, and step pace or intensity was not linked to cancer risk, suggesting that walking at any pace may confer protective effects, the study authors said.

The study’s use of wrist-worn accelerometers provided objective and precise measurements of physical activity, addressing limitations of prior research that relied on self-reported data, which can be subject to recall bias and inaccuracies, according to the authors. This prospective cohort study leveraged data from the UK Biobank accelerometer substudy, which included detailed activity tracking and health records.

Researchers emphasized that the results support current national and international physical activity guidelines, which recommend increasing daily movement for cancer prevention. “Our findings support the idea that simple low-intensity activities such as walking are associated with a lower risk of developing cancer,” the study said. The data suggest that individuals who are less active could benefit from increasing their daily step count to between 7,000 and 9,000 steps.

The study’s comprehensive adjustments for confounding factors, including BMI and lifestyle variables, and its focus on 13 specific cancer types, provide robust evidence linking physical activity to reduced cancer risk, according to the research team. The average follow-up of nearly six years allowed for sufficient time to observe incident cancer cases among participants.

The research builds on previous studies by incorporating objective accelerometer data rather than relying solely on questionnaires, thereby enhancing the accuracy of physical activity assessment. This approach fills gaps in earlier research that often used self-reported measures or BMI as proxies for activity, which can obscure the relationship between exercise and cancer outcomes.

The UK Biobank is a large, ongoing biomedical database and research resource containing in-depth genetic and health information from half a million UK participants. The accelerometer substudy provided detailed physical activity data that has been used in various epidemiological investigations, including this one.

The study’s implications extend to public health strategies aimed at cancer prevention through lifestyle modification. While the researchers did not establish causality, their findings add to the evidence base supporting physical activity as a modifiable factor associated with lower cancer incidence.

Future research may explore the biological mechanisms underlying the association between physical activity and reduced cancer risk, as well as investigate the potential benefits of different activity patterns across diverse populations. The authors noted that their findings reinforce the importance of promoting physical activity in middle-aged and older adults to potentially reduce cancer burden.