Health
Build a cancer-resistant body: the exercise connection you need to know
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Harness the natural healing power of exercise as Paula Goodyer explains its role in preventing cancer. She writes that science is revealing new ways that physical activity interacts with our body's systems to create an environment that's hostile to cancer cells.
By Paula Goodyer
How exercise helps prevent cancer
Exercise is our ally when it comes to preventing or surviving cancer. It lowers the risk of around a dozen cancers, with the strongest evidence for bowel, breast, bladder, gastric, oesophageal, kidney, prostate and endometrial cancers.
Keeping off extra weight is part of the story - overweight and obesity cause almost 5,300 cases of cancer in Australia each year, according to Cancer Council Australia.
”If someone is overweight and especially if they have diabetes, they will have a high level of insulin that can act like a growth hormone, stimulating cancer cells to develop,” explains Professor Rob Newton of Edith Cowan University’s Exercise Medicine Research Institute.
“This is why too much fat and too little muscle in the body create a cancer-promoting environment. But regular strength training to build more muscle can improve body composition and develop a more cancer suppressive environment in the body.”
Our muscles do so much more than help us move. They work like an endocrine organ in their own right that interacts with every system in the body, including the immune system - and that’s one reason why exercise helps prevent cancer and improve cancer survival, he explains.
”In general, our bodies produce cancerous cells all the time and it’s the immune system’s job to identify and destroy any potentially cancerous cells. When muscles move, they activate the immune system which sends in T cells to destroy any cancer cells,” he says.
“Exercise also increases blood flow and oxygen to the body’s cells and that helps slow cancer down and reduce the risk of it spreading - that’s because a low oxygen environment favours cancer cells and drives their spread.”
How exercise creates a cancer - fighting substance
Last year a study by the UK’s Newcastle University of older men with risk factors for bowel cancer - like being overweight or physically inactive - found that after 30 minutes of pedalling an exercise bike, blood tests showed they produced a cancer-fighting substance called IL-6 capable of repairing damaged cells.
When researchers added the blood samples to bowel cancer cells in the lab, the samples taken immediately after exercise reduced DNA damage and slowed the growth of these cells.
“These findings are exciting because they show a mechanism underlying how physical activity reduces bowel cancer risk that’s not dependent on weight loss,” says researcher Dr Sam Orange.
As for breast cancer, now the most common cancer in the world, there’s strong evidence that physical activity helps prevent it. Exercise helps by reducing too high levels of hormones like oestrogens and androgens that drive around 70% of breast cancers, explains Associate Professor Brigid Lynch, Deputy Head of the Cancer Epidemiology Division at Cancer Council Victoria.
“It also helps people maintain a healthy body size - we know that these hormones are produced by fat tissue, especially after menopause,” she says, adding that prostate, endometrial and ovarian cancers are also linked to high levels of these hormones.
How much exercise does it take to help prevent cancer? Just 30 minutes of moderate intensity exercise each day is good for our general health but upping this to 60 minutes can reduce your risk of developing cancer according to the Cancer Council Australia - and there’s evidence to suggest that the more exercise we do, the lower the risk - especially if it’s more vigorous physical activity.
“And don’t forget to include strength training at least twice per week to build muscle size and an anti-cancer environment," Professor Newton adds.
Read more about health and exercise on Citro:
- Natural therapies to get you a good night's sleep
- Hello muscles: 10 benefits of strength training
- Is intermittent fasting really the fountain of youth? Here's what the science says
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