How exercise cuts your cancer risk

With science on their side, researchers are sharing one important truth: Avoid inactivity!

There is plenty of evidence linking higher physical activity levels to lower risks of several types of cancer.

One of the latest studies, published in JAMA Internal Medicine reviewed data collated from 12 studies, measuring the exercise habits of 1. 44 million people, aged 19-98, over the course of 11 years. Researchers matched their exercise records with the development of 26 types of cancer.

People who were more active had on average a 20% lower risk of 13 cancers, including of the oesophagus, lung, kidney, stomach, endometrium and others, compared with people who were less active. The most active people benefited from a 7% lower risk of developing any type of cancer than the least active of the study group.

This recent study supports previous evidence, which has found that people who are more active tend to have lower rates of colon, breast and endometrial cancer specifically. Exercise has a number of biological effects on the body. Although the exact mechanisms are not completely clear, scientists suggest that exercise might prevent cancer development in the following ways.

• Lowering the levels of hormones, such as insulin and oestrogen, and of certain growth factors that have been associated with cancer development, such as breast and colon cancers.
• Helping to prevent obesity and decreasing the harmful effects of obesity, particularly the development of insulin resistance.
• Reducing inflammation, and thus potential tumour formation.
• Improving immune system function.
• Altering the metabolism of bile acids, resulting in decreased exposure of the gastrointestinal tract to these suspected carcinogens in colon cancer, detailed in a study in Cancer Epidemiology, Biomarkers & Prevention.
• Enhancing the digestive process, and accelerating the removal of waste, which decreases gastrointestinal tract exposure to possible cancer-causing agents
• Repairing DNA when it is damaged by cancer-promoting substances.

Lead author of the JAMA study, cancer epidemiologist, Steven Moore, says that there is a strong relationship between leisure-time, physical activity and lowered risk to cancer, even after adjusting for other potential factors such as high body mass index (BMI), poor diet and smoking.
“Health care professionals counseling inactive adults should promote physical activity as a component of a healthy lifestyle and cancer prevention,” he said.

Researchers from the US National Cancer Institute, the National Institutes of Health, and the American Cancer Society, agree that physical activity should be promoted as a key component of population-wide cancer prevention and control efforts.

Most experts recommend a minimum of 30 – 60 minutes of physical activity daily. This can be accumulated through the day via ‘incidental’ exercise such as using the stairs instead of the lift, or taking the dog for a brisk walk. Make exercise part of your life in a sustainable way by choosing something you love to do, and doing it with friends or a training buddy. Schedule your exercise time and try to keep at it, suggests Discovery Vitality biokineticist, Stephanie Donaldson, as the most benefit is derived from being consistent.

Physical activity is not only one of the cornerstones of cancer prevention, it also has profound effects for those undergoing active treatment, or post treatment.

Regular activity is likely to have benefits for cancer survivors, including:

• Weight maintenance: A study found that weight gain after breast cancer diagnosis was linked to poorer outcomes. “Compared with women who maintained their pre-diagnosis weight (within 5%), those who gained more than 10% after diagnosis had worse survival.” The effect was more pronounced during the first two years after diagnosis.
• Quality of life: A Cochrane review revealed that physical activity may specifically affect: body image, emotional well-being, sexuality, sleep, anxiety, fatigue and pain. Further, in a British Medical Journal study exercise is found to reduce depression and to improve physical functioning, social functioning, and mental wellbeing.
• Preventing cancer recurrence or progression and prognosis: A 2014 study in Annals of Oncology concluded that: “Among breast and colorectal cancer survivors, those who performed physical activity before or after cancer diagnosis showed reduced mortality risk.”
• Another study (in JAMA) found that women who exercised moderately (such as walking 3 to 5 hours per week at an average pace) after a breast cancer diagnosis had 40% to 50% lower risks of breast cancer recurrence, death from breast cancer, and death from any cause compared with more sedentary women.
• Better outcomes are also seen in colorectal cancer: In one 2015 study from the Journal of Oncology, those who engaged in leisure-time physical activity had a 31% lower risk of death than those who did not, even if they weren’t active before diagnosis. And in prostate cancer: Men with prostate cancer which has not metastasized who engaged in vigorous activity for at least 3 hours per week had a 61% lower risk of death from prostate cancer compared with men who engaged in vigorous activity for less than 1 hour per week.
• Enhancing the digestive process, and accelerating the removal of waste, which decreases gastrointestinal tract exposure to possible cancer-causing agents
• Repairing DNA when it is damaged by cancer-promoting substances.

It’s clear that everybody benefits from exercise, but the benefits can be all the more profound in cancer patients.

Vitality Active Rewards

Set a personalised training goal… Join a gym, participate in a parkrun, use a fitness device – and get active. While you’re improving your health and fitness, you’ll be rewarded with Vitality Active Rewards points to redeem at a number of partners.