Physical activity and risk of cancer in the UK statistics

While it is difficult to separate the effects of physical inactivity from those of increased bodyweight, there is consistent evidence that people with higher levels of physical activity have a reduced risk of colon, breast and endometrial (womb) cancer that is independent of bodyweight.

• Around four in ten men and around three in ten women in England meet government physical activity recommendations.
• Three in ten men and almost four in ten women in England do less than 30 minutes of moderate physical activity per week.

section reviewed 01/06/05
section updated 01/06/11

A meta-analysis of 54 studies reported a 24% risk reduction for colon cancer in the most versus least active men, and a 21% risk reduction in the most active women. Results from both case-control and cohort studies supported the protective association between physical activity and colon cancer.1

Physical activity may affect colon cancer risk in various ways, including by reducing faecal transit time, inflammation and insulin resistance and modifying hormone metabolism.3,4

About 50 studies have looked at the association between physical activity and breast cancer, showing a 15-20% risk reduction for the most active women.5 The risk reduction could be because exercise alters hormone levels.6,7

The most active women have a 20-30% reduced risk of endometrial cancer compared to the least active women, according to a meta-analysis of prospective studies.8 This may be because physical activity reduces levels of serum oestrogen and circulating insulin.8

A study published in December 2011 estimated that more than 3% of breast cancers, more than 5% of colon cancers, and around 4% of endometrial cancers in 2010 were linked to people doing fewer than 150 minutes of physical activity per week.33 Much higher estimates of the proportion of breast cancers (around 18%) and colon cancers (around 19%) due to physical inactivity in the UK have subsequently been published.22 However, it is thought that the way the study was designed may have exaggerated the attributable risk proportion.

A meta-analysis found evidence that people who participate in higher levels of recreational physical activity have a lower risk of lung cancer.9

Since that analysis, results of studies into physical activity and lung cancer risk have been inconsistent.10-13

Some studies have shown a reduced risk of pancreatic cancer for people doing moderate amounts of physical activity,14,15 but other studies do not show an association,16,17 and a recent meta-analysis showed no association of leisure time physical activity on risk of pancreatic cancer.24

There is evidence from three cohort studies that men who are physically active have a reduced risk of advanced prostate cancer.18-20    A recent cohort study showed that men who are more active in their jobs, or do more physical activity throughout their lifetime have a reduced risk of prostate cancer overall.25 The European Prospective Investigation into Cancer showed no association of leisure-time physical activity with prostate cancer risk, although results were indicative of a reduction in risk of advanced prostate cancer with occupational physical activity.28 Another very large cohort study showed no association of physical activity with prostate cancer risk in white men, although there was a risk reduction for black men.29

section reviewed 01/06/05
section updated 01/07/12

Physical activity recommendations for people in the UK were updated in July 2011, as follows:30

• Early years (under 5s): After beginning to walk, under fives should be physically active for at least 180 minutes per day;
• Children and young people (5-18 years): At least 60 minutes of moderate to vigorous physical activity per day. Vigorous intensity activities that strengthen muscle and bone should be carried out on at least three days a week;
• Adults (19+ years): At least 150 minutes of moderate intensity physical activity over a week, in bouts of 10 minutes or more. Physical activity to improve muscle strength should be carried out on at least two days per week.

Levels of physical activity in men and women in England have increased since 1997, but are still relatively low, with 39% of men and 29% of women currently doing at least 150 minutes per week.26 Levels of physical activity decline with age, and in all age groups women are much less likely to meet recommendations than men (Figure 3.1). Physical activity levels are similar elsewhere in the UK.23,31,32

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While exercise levels have increased since 1997, 30% of men and 38% of women in England still do less than 30 minutes of moderate or vigorous physical activity a week.26

In England, 70% of boys and 59% of girls aged 2-15 are doing at least 60 minutes of moderate intensity activity per day.27

section reviewed 01/06/05
section updated 01/07/12