Keeping physically active can significantly cut the risk of colon cancer, international research shows.
Vigorous housework: good for fitness, and cancer risk
Scientists analysed data from 413,000 people in 10 European countries, and found physically active people were 22% less likely to develop the disease.
They said an hour a day of vigorous physical activity or two hours of moderate activity would be enough to reduce the risk.
The study appears in Cancer Epidemiology and Biomarkers Prevention.
The study found the risk of tumours on the right side of the colon was reduced by as much as 35% for most active people.
For active people who were not overweight the risk was reduced even further.
Housework a good option
Dr Lesley Walker, of the charity Cancer Research UK, said: "This is a very large study which should remove any doubt about the benefits of exercise in relation to reducing the risk of bowel cancer.
"It is important for people to understand that they can take steps in their daily routine to reduce cancer risk. You don't need to join a gym to get the benefit of exercise.
"If regular brisk walking or going for a run doesn't appeal you can do some strenuous housework.
"Cleaning windows, vacuuming and scrubbing floors burn off a lot of calories.
"So does gardening or cleaning the car.
"If you combine regular physical activity with a good diet you are more likely to maintain a healthy body weight which will also significantly help to reduce your risk of bowel cancer."
Dr Walker said it was unclear why the benefits of physical activity were particularly pronounced on the right side of the colon.
However, physical activity was known to stimulate waves of muscle contraction down the right side of the colon which accelerates movement of waste and the possible cancer-causing agents in it.
Among the 21,500 cases of colon cancer diagnosed each year in the UK, approximately half are detected on the right-hand side of the colon.
The study was part-funded by Cancer Research UK and the Medical Research Council.
It is part of the European Prospective Investigation into Cancer and Nutrition (EPIC) study.