Doctors harp on exercise.
Despite the harping – or in my case, perversely because of it – I avoid exercise like the plague.
Even so, as I read more and more sites promoting the “exercise makes you better if you have breast cancer” meme, I found that almost none of them give any kind of evidence as to WHY exercise fights cancer and promotes healing.
So I dug into the sites and finally found some evidence supporting this wild, “Do this one weird thing…” kind of meme. This week, it’s number:
9) Physical activity appears to enhance proliferation of lymphocytes, increases the number of natural killer cells and increases lymphokine-activated killer cells activity.What’s a “lymphocyte”?
What’s a “natural killer cell”?
What’s “lymphokine-activated killer cell activity”?
To tell you the truth, these appear to fade from easily definable to mumbo-jumbo-ish, so let’s have at it!
But we need to take one more step backward and start with White Blood Cells.
In contrast to the RED blood cell, which are the cells that make up the visible part of the blood. The red blood cells – or rbc’s – are the part of the blood that makes it RED! It’s red because each of the rbc’s has many heme molecules in it. The heme molecules are the ones that carry a tiny iron atom in their center. It’s the iron atom that OXYGEN grabs hold of so that the rbc’s can carry oxygen from the lungs, allowing cells everywhere to "BREATHE" (technically to carry on cellular respiration...but this isn't a textbook). There are zillions of these little suckers in your bloodstream at all times and THEY come from the marrow in your bones.
So white blood cells – or wbc’s – don’t have heme in them; therefore they are, by comparison, WHITE. But they still travel in the bloodstream. Instead of carrying oxygen, they attack and destroy any germs that get into your body. They also take care of any other junk that gets in.
Lymphocytes are a kind of wbc. There are three kinds of lymphocytes – natural killer cells, T cells and B cells. Another name for the natural killer cells are NK cells. T cells are the kind of cells that the Human Immunodeficiency Virus (HIV) targets.
NK cells have the specific duty of protecting the body from tumors and viruses by “popping” the cells to destroy them; the other two handle the release of cytokines, lysis and immune regulation and creating antibodies.
The effect of exercise on NK cells however, seems to be blasted out of the water by the study referenced below and quoted here: “…latent CMV infection is associated with lowered numbers of NK-cells expressing inhibitory receptors and a blunted mobilization of NK-cells in response to acute exercise. This may indicate a compromised immune response to ‘fight-or-flight’ situations in those infected with CMV.”
Conversely, “Moderate exercise has been reported to produce an anti-inflammatory environment and thus reduce the risk of infection. Conversely, continuous, intense exercise may increase oxidative stress (an overproduction of reactive oxygen species compared to the body’s ability to detoxify), inflammatory responses, as well as the risk for infection.”
And blasting back from the other side: “Longitudinal training studies in previously sedentary people have failed to show marked changes in T and B cell functions provided that blood samples were taken at least 24 h after the last exercise bout.” Also: “Evidence suggests that the prophylactic effect of exercise may, to some extent, be ascribed to the anti-inflammatory effect of regular exercise mediated via a reduction in visceral fat mass and/or by induction of an anti-inflammatory environment with each bout of exercise (e.g. via increases in circulating anti-inflammatory cytokines including interleukin (IL)-1 receptor antagonist and IL-10). To understand the mechanism(s) of the protective, anti-inflammatory effect of exercise fully, we need to focus on the nature of exercise that is most efficient at allieviating the effects of chronic inflammation in disease. The beneficial effects of endurance exercise are well known; however, the antiinflammatory role of strength training exercises are poorly defined. In addition, the independent contribution of an exercise-induced reduction in visceral fat versus other exercise-induced anti-inflammatory mechanisms needs to be understood better. There is consensus that exercise training protects against some types of cancers. Training also enhances aspects of anti-tumour immunity and reduces inflammatory mediators. However, the evidence linking immunological and inflammatory mechanisms, physical activity, and cancer risk reduction remains tentative.”
Translated: “We don’t know enough yet to say if exercise is magic”.
I’m NOT saying exercise is a waste of time. There are enough other benefits listed above to induce anyone who is hesitant or ridicules the IMPORTANCE of exercise in fighting and recovering from cancer (in this case breast cancer specifically) to start a regimen of moderate exercise and make it a regular part of life.
BUT if anyone says that the data are in and it’s a win and then runs out to hire a trainer or join an exclusive club offering personal coaching and cutting edge vegetable-fruit mixed drinks…well, like everything else that has to do with breast cancer, there’s no “cure all”, no magic bullet and nothing that works for everyone all the time.
Resources: http://en.wikipedia.org/wiki/Lymphocyte, http://www.ncbi.nlm.nih.gov/pubmed/21933704, http://www.nsca-lift.org/HotTopic/download/Immune-Function.pdf, http://www.ncbi.nlm.nih.gov/pubmed/21446352
Image: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEho2hgCC9tHO2iEZsKGEqnFHMCX2akUSi5fgEg6LmwALVLbD4sg0TQqsN5F5R8Qwaf3MVwKV072SFbUgd2nAZGBPZLbEd19V6HxPUgneVrCi0WbwCmQeU2VH1r9F3hyGmcqk85qk5NOa8Y/s1600/white-blood-cell-amungst-red.jpg
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