August 11, 2016
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Q: I know exercise has been proven to be beneficial to my cardiovascular and mental health as well as for controlling my weight. What does science have to say about its role in cancer?
A: The impact of exercise on various cancers has long intrigued scientists and been the subject of spirited debate.
When epidemiological studies compare those who exercise versus those who do not, the exercisers, in general, were far less likely to die from various cancers. And yet, exercise involves putting a biological stress upon the body which leads to short-term inflammation throughout. Since we believe that many cancers are partially a result of inflammation, there have been some who have questioned whether exercise is really all that helpful.
In order to get a better understanding, the American-based National Cancer Institute, in conjunction with Harvard Medical School and a number of other institutions, combined the data from 12 previously-conducted studies that were judged to be both well-designed and without obvious bias.
The pool of people wound up involving 1.44-million men and women, and researchers focused in on specific information as to the degree they engaged in physical activity (i.e. how often and how vigorously) and, of course, whether and when, after each study’s start, a participant was diagnosed with any form of cancer. Then using statistical analyses, they computed the role that exercise seemed to be playing in people’s risk for cancer.
It turns out, that exercise seems to play a much larger role than scientists had previously thought. The results seemed to corroborate previous evidence about exercise’s benefits in the reduction of the risk of breast cancer in women and lung and colon cancer in both sexes. It also presented new findings that showed that exercise seems to also reduce the chances of having tumours in the liver, esophagus, stomach, kidneys, blood, endometrium, rectum, bladder, bone marrow, head and neck. These reductions were seen even in those who exercised moderately and for minimal periods of time.
That being said, not surprisingly, the benefits grew in proportion to the degree to which the participant engaged in exercise. When the top 10 per cent of exercisers were compared to the 10 per cent least active, the exercisers were as much as 20-per-cent less likely to develop most of these cancers.
There was also good news for those of us who are active despite carrying a few extra pounds around our waistlines. The researchers found that the reductions in cancer risk held true for the overweight or even obese compared to those of similar weights who were not as active.
For those of us who like to know the answer to the question why, another study out of Denmark looked at the impact of exercise on mice in an attempt to understand the biochemical basis of this effect. To do this, all of the mice involved were implanted with skin cancer cells and then subjected to varying levels of exercise.
As we would have guessed from human studies, the mice that exercised more had fewer and smaller cancerous lesions than the sedentary mice. What was of greater interest, was that the active mice had much higher levels of the neurotransmitter adrenalin (our “flight or fright” body chemical that allows us to react to emergency situations), interleukin-6 (a substance released by muscles when they are worked) and, perhaps most importantly, a type of immune cell known as natural killer cells that are known to be potent cancer fighters.
It was hypothesized that the increased levels of adrenalin exerted an effect on the interleukin-6 (IL-6), making the IL-6 more alert to the development of tumours within their bodies. When a tumour was, indeed, recognized by the immune system, the IL-6 cells then activated the natural killer cells and directed them to the tumours where they attacked the tumours.
In short, these changes seem to suggest that exercise changes the way the immune system deals with cancer in a natural and safe manner. Given all the other proven benefits of regular exercise, we find it very disappointing that more people don’t find the time or energy to engage in a regular walk, at the very least. The dividends to your health will be both immediate and life-long.
For more information about this or any other health-related questions, contact the pharmacists at Gordon Pharmasave, Your Health and Wellness Destination. Also check the website at /www.gordon-pharmasave.com/ and the Facebook page at www.facebook.com/GordonPharmasave/?fref=ts
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