Men who regularly engage in cardio exercises such as jogging, swimming or cycling could be cutting their risk of nine cancers, a new study suggests.
Those with good cardiorespiratory fitness are far less likely to go on to develop cancers of the head and neck, stomach, pancreas, liver, bowel, rectum, kidney, lung and oesophagus, researchers found.
In the new study, published in the British Journal of Sports Medicine, experts from Sweden tracked about a million men for an average of 33 years.
The men involved in the study were conscripted into military service in Sweden between 1968 and 2005.
At the start of their conscription, the men underwent a battery of tests assessing a number of factors including their height, weight, blood pressure, muscle strength and cardiorespiratory fitness.
During the follow-up period, about 84,000 developed cancer.
Study author, Dr Aron Onerup, told The National that there were several physiological benefits of exercise which interact to reduce the risk of cancer.
In terms of the amount of cardio exercise needed for significant risk reduction, Dr Onerup said it was linear.
"Those with moderate fitness had lower risk than those with low fitness, while those with high fitness had even lower risk," he said.
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Researchers found that, compared with those with low cardiorespiratory fitness, men with a higher level of cardiorespiratory fitness were:
– 19 per cent less likely to develop head and neck cancer
– 39 per cent less likely to develop cancer of the oesophagus
– 21 per cent less likely to develop stomach cancer
– 40 per cent less likely to have liver cancer
– 18 per cent less likely to develop bowel cancer and 5 per cent less likely to develop cancer of the rectum
– 20 per cent less likely to develop kidney cancer
– 42 per cent less likely to develop lung cancer
– 12 per cent less likely to develop pancreatic cancer
“These results could be used in public health policymaking, further strengthening the incentive for promoting interventions aimed at increasing [cardiorespiratory fitness] in youth,” the authors wrote.
The researchers did find that higher cardiorespiratory fitness was linked to a slight (7 per cent) increased risk of prostate cancer and a 31 per cent increased risk of skin cancer.
Dr Onerup said: "The association between fitness and cancer differed between cancer sites. While we did see associations both for head and neck cancers and kidney cancers, the associations were consistent for tumors in the gastrointestinal tract"
A previous study examining the same data set suggested the slight increase in risk for prostate cancer was not linked to a higher rate of aggressive prostate cancer or prostate cancer death, and could be attributable to increased screening.
The authors suggested a higher skin cancer rate could be explained due to “higher UV exposure”.