Studies have identified factors that can reduce the risk of developing cancer and provided guidance regarding improving modifiable risk factors, including sedentary lifestyle, smoking, alcoholism or an inadequate diet, among others. For these modifiable risk factors, it has been proven that physical exercise acts as a protective factor and reduces the chances of developing cancer. But could something as simple as walking offer real protection?
It turns out the answer may be yes.
Recent findings from the University of Oxford add more weight to that idea (1). According to a large study involving 85,394 people in the UK, the more steps you take each day, the lower your chances of developing up to 13 different types of cancer. In the study, participants wore activity trackers that measured both the amount and intensity of their daily movement. On average, researchers followed up with participants six years later. They found a clear pattern: more steps meant lower cancer risk, regardless of how fast those steps were taken.
The benefits began to appear at around 5,000 steps a day – anything below that didn’t seem to offer much protection. At 7,000 steps, the risk of developing cancer dropped by 11%. At 9,000 steps, it dropped by 16%. Beyond 9,000 steps, the benefits levelled off. The difference in risk reduction became marginal and varied slightly between men and women.
These findings support the popular recommendation of aiming for 10,000 steps a day – not just for general health, but potentially for cancer prevention too. These associations also held up when results were adjusted for demographic, BMI and other lifestyle factors, such as smoking, suggesting that the observed changes in cancer risk were indeed down to the average number of daily steps a participant took.
Step intensity was also analyzed – essentially, how fast participants were walking. Researchers found that faster walking was linked with lower cancer risk. However, when total physical activity was taken into account, the speed of walking no longer made a statistically significant difference. In other words: it’s the total amount of walking that counts; not how brisk it is. Likewise, replacing sitting time with either light or moderate activity lowered cancer risk – but swapping light activity for moderate activity didn’t offer additional benefits. So just moving more, at any pace, appears to be what matters most.
The researchers looked at 13 specific cancers, including esophageal, liver, lung, kidney, gastric, endometrial, myeloid leukemia, myeloma, colon, head and neck, rectal, bladder and breast. Over the six year follow-up period, around 3% of participants developed one of these cancers. The most common were colon, rectal, and lung cancers in men, and breast, colon, endometrial, and lung cancers in women. Higher physical activity levels were most strongly linked to reduced risk of six cancers: gastric, bladder, liver, endometrial, lung and head and neck.
The study also stands out because it didn’t focus solely on vigorous exercise. Many past studies have shown that intense workouts can reduce cancer risk – but not everyone is able (or willing) to hit the gym hard. This new research shows that even light activity like walking can make a difference, making cancer prevention more accessible to more people.
Being physically active also greatly benefits individuals with a cancer diagnosis: the Canadian Cancer Trials Group (CCTG) launched the CO.21 Colon Health and Lifelong Exercise Change (CHALLENGE) trial, (2) a phase 3 randomized trial comparing the effects of providing health-education materials alone or such materials plus a 3-year structured exercise program in patients with colon cancer who had completed adjuvant chemotherapy.
Patients were eligible for the trial if they had a complete resection of stage III or high-risk stage II adenocarcinoma of the colon (with the latter defined as a T4 tumor with resection of fewer than 12 lymph nodes and poorly differentiated histologic findings). All the patients also had completed adjuvant chemotherapy within the past 2 to 6 months, reported that they were currently exercising less than the equivalent of 150 minutes per week of moderate-to-vigorous intensity, and were able to complete at least two stages of a submaximal treadmill test (walking at a casual pace for 6 minutes) or the 6-minute walk test.
Exercise significantly reduced the relative risk of disease recurrence, new primary cancer, or death by 28%. The disease-free survival curves began to separate at about 1 year and continued to separate over the 10-year follow-up, with an absolute between-group difference of 6.4 percentage points at 5 years. Moreover, exercise reduced the relative risk of death by 37%. The overall survival curves began to separate at about 4 years and continued to separate over the 10-year follow-up, with an absolute between-group difference of 7.1 percentage points at 8 years. The magnitude of benefit from exercise delivered after surgery and adjuvant chemotherapy was similar to that of many currently approved standard drug treatments.
The researchers found that a 3-year structured exercise program that was initiated within 6 months after the completion of adjuvant chemotherapy for colon cancer improved disease-free survival. The intervention also resulted in findings that were consistent with improved overall survival, patient-reported physical functioning, and objective physical functioning and fitness as compared with health education alone, with only a modest increase in musculoskeletal adverse events. Their trial provides robust evidence of a substantial benefit-to-harm ratio in favor of structured exercise over a sedentary lifestyle and supports its incorporation into standard care. Knowledge alone, however, is unlikely to change patient behavior and outcomes. To achieve meaningful increases in exercise will require that health systems invest in behavior-support programs.
Of course, the link between physical activity and cancer is complex. More long-term research is needed, especially focused on individual cancer types, to better understand why walking helps – and how we can make movement a regular part of cancer prevention strategies. But for now, the message is clear: sit less, move more – and you could walk your way toward better health.(3)
