What do we know about physical activity and cancer?

Welcome to our information pages on physical activity and its links to bowel, breast, womb and lung cancers. Follow the links to bring you to the relevant section :

What do we know about physical activity and bowel cancer?

A lot of research has been carried out into the link between physical activity and bowel cancer. Most of this research has consistently found that adults who increase their physical activity can reduce their risk of developing bowel cancer by 30 to 40 per cent (see note 1 below). And the more active you are, the more you reduce your risk. It is estimated that 30 to 60 minutes of moderate to vigorous physical activity every day offers the most protection against bowel cancer (see notes 2 & 3 below).

Physical activity most likely affects your risk of bowel cancer in a number of ways. For example:

  • Physical activity leads to regular bowel movements and may therefore reduce the time the bowel is exposed to potential cancer-causing substances.
  • Physical activity reduces inflammation of the bowel, which might otherwise increase your bowel cancer risk. 
  • Physical activity reduces the amount of insulin and some other hormones in your body. At high levels, these hormones can encourage the growth of cancer cells.

What do we know about physical activity and breast cancer?

The link between physical activity and breast cancer has been widely studied, with over 60 studies published in North America, Europe, Asia, and Australia. Most studies show that physically active women have a lower risk of developing breast cancer than inactive women. However, the extent to which physical activity reduces breast cancer risk varies widely - between 20 to 80 per cent (see notes 2 & 3 below).

While the evidence tells us that physical activity reduces breast cancer risk in both premenopausal and postmenopausal women, young women who are physically active appear to reduce their risk the most. A number of studies also suggest that the effect of physical activity may be different depending on your body mass index (BMI), with women in the normal weight range benefitting the most. Most studies suggest that 30 to 60 minutes per day of moderate to vigorous physical activity offers the greatest protection against breast cancer (see notes 1, 2 & 3 below).

Physical activity is thought to reduce breast cancer risk by lowering the amount of insulin and some other hormones in your body. At high levels, these hormones can encourage the growth of cancer cells.  Physical activity also helps you to keep a healthy weight, which also reduces your risk of breast cancer.

What do we know about physical activity and womb cancer?

About 20 studies have examined the link between physical activity and womb cancer risk. The results consistently tell us that the more active you are, the more you reduce your risk of womb cancer. These studies suggest that women who are physically active reduce their risk of womb cancer by 20 to 40 per cent, regardless of their age(see notes 1 & 3 below).

Physical activity is thought to reduce womb cancer risk by lowering the amount of oestrogen and other sex hormones in your body. At high levels, these hormones can encourage the growth of cancer cells.  Physical activity also helps you to keep a healthy weight, which also reduces your risk of womb cancer.

What do we know about physical activity and lung cancer?

At least 21 studies have examined the impact of physical activity on the risk of lung cancer. Overall, these studies suggest that physically active people reduce their risk of lung cancer by about 20 per cent (see notes 1 & 3 below). The link between physical activity and lung cancer risk is less clear for women than it is for men. 

The above information has been adapted from the National Cancer Institute.

References

1. IARC Handbooks of Cancer Prevention. Weight Control and Physical Activity. Vol. 6. 2002

2. Lee I, Oguma Y. Physical activity. In: Schottenfeld D, Fraumeni JF, editors. Cancer Epidemiology and Prevention. 3rd ed. New York: Oxford University Press, 2006

3. McTiernan A, editor. Cancer Prevention and Management Through Exercise and Weight Control. Boca Raton: Taylor & Francis Group, LLC, 2006