Exercise against cancer

Cancer is often referred to as a single condition, in actual fact it consists of more than 100 different diseases. (In fact, there are 210 types of diseases classified under the umbrella name of cancer.) These diseases are characterised by uncontrolled growth and spread of abnormal cells.

Facts & Figures:

  •  Cancer strikes 11 million adults and children every year throughout the world and 6 million die from it annually (MAKNA).
  •  Worldwide 10 million people developed malignant tumours and 6.2 million died from cancer in the year 2000.  Global cancer rates are expected to increase 50% by the year 2020, according to the 2003 World Cancer Report from the International Agency for Research on Cancer (IARC), a branch of the World Health Organization (WHO).
  •  IN MALAYSIA, 45,000 Malaysians are told every year that they have cancer. It is the second leading cause of death here after heart disease (MAKNA).  According to a 2007 WHO report, cancer is among the top 5 diseases affecting Malaysians, besides high blood pressure, osteoporosis, diabetes and heart disease (Star, 6.8.07).
  •  1 in 4 Malaysians can be expected to get cancer in his or her lifetime (Malaysian National Cancer Registry, 2002). Every year at least 40,000 Malaysians get cancer. And this, according to former Health Minister Datuk Dr Chua Soi Lek, is only a conservative figure (NST, 22.11.05).
  •  All of us have cancerous cells in our body.  Cancer is when cells in the body go out of control. But the good news is: 65-85% of cancers can be prevented — through diet and lifestyle changes. Exercise is a good preventive measure.
  •  In the past decade alone, over 200 population-based studies have been done on physical activities and cancer risks (BMJ editorial, 9 December 2000). The verdict: Cancers of the breast, prostate, lung and uterus can all be prevented with regular exercise.  Particularly, there is evidence that high levels of physical activity can work to prevent colon cancer — one of the 6 most common cancers in Malaysians.

What Studies Show:

  •  IN a large study of over 17,000 Harvard alumni, aged 30-79, vigorous activity was associated with a significant decrease in the risk of developing colon cancer.  Highly active individuals (energy expenditure of more than 2,500 Kcal* per week) had half the incidence of those that expended less than 1,000 Kcal* per week (Lee et al., 1991). [* A Kcal (kilocalorie) is the technical term for a calorie.]
  •  A Stanford University study that looked at colon cancer risks among Chinese men and women living both in the People’s Republic of China, and the United States, among others, found that the group that spent the most time sitting (reflecting sedentary lifestyles and occupations) had the highest incidence of colon cancer  (Whittemore et al. 1990).
  •  A large study found that women who walked briskly for 1.25-2.5 hours per week had an 18% reduction in breast cancer risk. Those who walk 10 hours or more per week had a little more risk reduction (Journal of the American Medical Association, 10 September 2003).
  •  Regular exercise also lowers death risks in breast cancer sufferers.   In a large, well-respected Nurses’ Health Study, which looked at 2,296 women with stages I, II and III breast cancer, diagnosed between 1984 and 1996, it was found that: Risk of death from breast cancer was reduced by 19% in those who walked or did similar exercises 1-3 hours per week, by 54% for those walking 3-5 hours per week (30 minutes a day), 42% for those walking 5-7 hours per week (60 minutes a day) and 29% for those putting in over 7 hours of exercise per week (findings by researchers from Brigham and Women’s Hospital and Harvard University, US).
  •  A survey based on information collected over a 23-year period in a research project called the Copenhagen Male Study found that regular exercise can help prevent intestinal cancer. The study comprised 5,000 men divided into 4 separate groups ranging from those who exercise very little to those who exercise a lot. Doctors examining the material believe that moderate physical activity strengthens the immune system and therefore helps prevent the cancer from developing (PreventDisease.com, July 2004).
  •  In Scotland, experts who combined and analysed the results of more than 50 separate studies into bowel cancer found that people who exercised regularly were 50% less likely to develop the disease (Scottish findings, 2001).
  •  Women who stay highly active throughout life are less likely to develop ovarian cancer.   A study of more than 2,100 women found that those who exercised more than 6 hours per week were 27% less likely to develop ovarian cancer than women who exercised less than 1 hour each week (Obstetrics and Gynecology, October 2000).
  •  Walking for 60 minutes a day, or doing housework for 4 hours a day, reduced the risk of endometrial cancer by 30%, according to researchers from the Vanderbilt University Medical Center in Nashville and the Shanghai Cancer Institute in China (Findings presented at the 95th Annual Meeting of the American Association for Cancer Research in Orlando, 29 March 2004).
  •  Researchers at the University of Bristol suggest that physical activity could cut the risk of bowel cancer, and may help prevent breast, prostate, lung and endometrial cancer. Regular exercise reduced the chance of developing bowel cancer by 40-50%; and breast cancer by 30%, with stronger effects in post-menopausal women (BBC News, 18 October 2002).
  •  Exercise reduces markers of cancer risk.  In a study, 114 postmenopausal, overweight, sedentary women were put on a moderate exercise programme of 45 minutes a day, 5 days a week, for 1 year. After 1 year, the subjects were tested for 2 blood factors that show inflammation in the body — C-reactive protein (CRP) and serum amyloid A, which have been associated with cancer risk and survival. (These factors are often elevated in overweight people.)
  •  It was found that among obese women (those with a body mass index of 30 or higher), “concentrations of CRP declined steadily over the course of the year from a baseline of 0.40 milligrams per deciliter to 0.32 milligrams (Research findings from the Fred Hutchinson Cancer Research Center in Seattle, US).
  •  Never too late to start:  A study by the Fred Hutchinson Cancer Research Center in Seattle involving over 74,000 women shows that even post-menopausal women can reduce their risks of breast cancer by exercising. Moderate exercise, such as walking, cycling or swimming, 5 times a week had the greatest impact (US study reported in the Journal of the American Medical Association, 2003).

Read more about How Exercise Heals Various Diseases, How Effective Are Yoga, Meditation, Tai Chi and Qigong and How to Exercise for Different Illnesses in the CAP Guide, EXERCISE AS MEDICINE.