Replacing 15 minutes of sleep or sedentary behaviour with 15 minutes of movement are each linked to a two per cent reduced risk of cancer, new UCL research has found.
The new study, published in BMC Medicine, analysed the records of 59,218 people (55 per cent female) with an average age of 61.7 from the UK Biobank, a database of half a million volunteers taking part in medical research.
Smartwatches were used to track the movement of the daily movements of those people and, over an eight-year follow-up, some 2,385 cancers occurred in the group. Modelling was used to see how differences in daily movement was linked to cancer risk.
Previous research by other researchers has found strong evidence that higher levels of activity are linked to a lower risk of several cancers - including of the bladder, breast, bowel, kidney and stomach.
The UCL study, led by Dr John Mitchell (UCL Division of Surgery and Interventional Science), looked at areas such as how long people spent sleeping, sedentary behaviour such as watching TV, standing and then any movement and at what intensity.
They found that the more people moved, the lower their risk of cancer.
For example, replacing 15 minutes of sleep or sedentary behaviour with 15 minutes of movement were each linked to a 2% reduced risk of cancer.
Conversely, swapping 30 minutes of movement for 30 minutes of sedentary behaviour increased the risk by 8%, while swapping it for sleep increased the risk by 7%.
This was not just about doing more exercise, Dr Mitchell said, but how everyday activities like running for a bus or carrying home heavy bags of groceries can help maintain a healthy lifestyle which reduce your risk of getting cancer.
Dr Mitchell said: "We are tending towards what we call 24-hour movement guidelines where individuals have a menu of possible options which they can adapt to their lifestyle in order to help them mitigate their risk of disease over time.
"Our study showed that there's an increased risk of cancer for those who spend a lot of time sitting down.
"We also explored what might happen if people leading active lives reduced their levels of physical activity and found that they also face a higher cancer risk.
"Based on theoretical modelling, our study showed even losing two to three minutes per day of vigorous activity, such as running for a bus, and replacing it with sitting down, sleep or light activity increased their cancer risk.
"Other examples of vigorous activity - that is, anything which elevates your heart rate and makes you sweat - include sport, rushing up the stairs and carrying home heavy grocery bags.
"The take-home message is that for people already leading physically active lives, it's really important to maintain that level of activity as you get older.
Current NHS guidelines say adults should aim for at least 150 minutes of moderate intensity activity a week or 75 minutes of vigorous intensity activity a week.
They should also do strength activities that work all the major muscle groups (legs, hips, back, abdomen, chest, shoulders and arms) on at least two days per week.
Examples of moderate activity include very brisk walking (4mph or faster), cycling at 10mph-12mph, or badminton. Vigorous activity also includes hiking, jogging at 6mph or faster, fast cycling, basketball or tennis.
