A little more movement during the day may be linked to a lower risk of developing several cancers, according to new research from University College London.
The study suggests that replacing only 15 minutes of sitting or sleep with movement was associated with about a 2% lower cancer risk.
The findings were published in BMC Medicine. Researchers analyzed information from 59,218 adults in the UK Biobank, a major research project that follows the health and lifestyles of hundreds of thousands of people.
The participants were about 62 years old on average, and 55% were women. Their daily activity was measured using wearable devices rather than relying only on people to remember and report how active they were.
These devices allowed researchers to estimate how participants divided each day among sleep, sitting or other sedentary behavior, standing, and movement at different levels of intensity. The researchers then followed the group for about eight years.
During that period, 2,385 participants developed cancers included in the researchers’ analysis. The team used statistical models to examine how different ways of spending the 24 hours in a day were associated with cancer risk.
The main pattern was simple: people who moved more tended to have a lower risk. But the study also explored a more practical question—what might happen if a person replaced one type of daily activity with another?
Replacing 15 minutes of sleep with 15 minutes of movement was associated with about a 2% lower cancer risk. Replacing 15 minutes of sedentary time with movement was linked to a similar reduction.
The opposite pattern also appeared. Replacing 30 minutes of movement with 30 minutes of sedentary behavior was associated with an 8% higher risk, while replacing the movement with sleep was linked to a 7% higher risk.
This does not mean that sleep is unhealthy. Adequate sleep is essential for physical and mental health, and the study examined statistical substitutions within a fixed 24-hour day rather than showing that people should deliberately cut necessary sleep.
The research instead highlights an important idea about daily life. Every day contains only 24 hours, so spending more time on one behavior automatically means spending less time on something else.
Lead researcher Dr. John Mitchell of UCL said health researchers are increasingly thinking in terms of “24-hour movement” patterns. Rather than considering exercise, sitting and sleep as completely separate issues, this approach looks at how they fit together across the whole day.
The study also suggests that movement does not have to happen only during a planned workout. Everyday activities that raise the heart rate can contribute to an active lifestyle.
Running to catch a bus, quickly climbing stairs or carrying heavy grocery bags can all require meaningful physical effort. For many people, these short bursts may be easier to fit into daily life than a long gym session.
The researchers paid particular attention to vigorous activity, which means movement intense enough to make a person breathe harder, raise the heart rate and often sweat. Their modeling suggested that replacing even two or three minutes of vigorous activity each day with less active behavior was associated with higher cancer risk.
That finding may be especially relevant as people grow older. Physical activity often decreases with age because of changing routines, health problems, retirement or reduced mobility.
Mitchell said people who are already physically active should try to maintain that activity as they age. The results suggest that losing regular movement could matter, even when the decline seems small.
There are several possible reasons physical activity could influence cancer risk. Regular movement can help control body weight, improve the way the body handles insulin, reduce long-term inflammation and affect hormones that are linked to some cancers.
Previous research has found convincing evidence that greater physical activity is associated with lower risks of several cancers, including cancers of the breast, bowel, bladder, kidney and stomach. The new study adds information about how the balance of movement and inactivity throughout an ordinary day may be related to risk.
Current NHS guidance recommends that adults aim for at least 150 minutes of moderate activity each week or 75 minutes of vigorous activity. Adults are also advised to perform muscle-strengthening activities on at least two days each week.
Moderate activity can include brisk walking or cycling, while vigorous activity includes activities such as running, fast cycling and some sports. The appropriate level will vary with a person’s age, fitness and health.
The study has notable strengths, including its large sample, long follow-up and use of wearable devices. Device measurements can provide a more objective picture of movement than questionnaires alone.
However, the findings do not prove that replacing exactly 15 minutes of sitting with movement will directly reduce an individual person’s cancer risk by 2%. The researchers used observational data and statistical modeling, so the results show associations rather than direct cause and effect.
People who move more can also differ from less active people in diet, smoking, body weight, income, existing health and many other ways. Researchers can adjust for many of these differences, but no observational study can remove every possible influence.
The results also should not encourage people to sacrifice healthy sleep simply to exercise more. A better interpretation is that reducing unnecessary sitting and protecting regular movement may be useful parts of an overall healthy routine.
Overall, the study supports a practical message: movement accumulated throughout the day may matter, not just formal exercise. Small changes may seem modest individually, but maintaining an active pattern over many years could contribute to lower disease risk alongside other healthy habits.
Source: University College London.
