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:
5) Physical activity may decrease risk for various cancers by improving immune function
I was a biology major in college – not because I wanted to be a doctor when I grew up. Not because I loved animals. I was a bio major because I loved LIFE! (No, not THAT kind of life. I hated crazy parties with drunken young adults wandering around, trying to shout over obnoxiously loud music and the inevitable whiff of various and sundry “recreational substances” in use. Thanks, but no thanks…) I loved diatoms and dinosaurs; liver flukes and lilies; Euglena and elephantiasis...I didn’t have FUN with it always, but I loved it.
One of the “basic” classes I took was Immunology. I still have the text in my basement library. Published in 1978, it has absolutely NO mention of Acquired Immune Deficiency Syndrome – what we call AIDS. In fact, Immunology was an ELECTIVE class any bio major could take. No one HAD to take it because, after all, while interesting, the immune system wasn’t all THAT important in the broad sweep of things...
“The immune system is a system of biological structures and processes within an organism that protects against disease. In order to function properly, an immune system must detect a wide variety of agents, from viruses to parasitic worms, and distinguish them from the organism's own healthy tissue... [the system includes] enzymes, phagocytosis (cells that eat other cells – the white blood cell in particular), antimicrobial peptides (molecules that kill microscopic creatures), and the complement system (a biochemical cascade that attacks the surfaces of foreign cells – one you might know is “histamine” – most of you reading this have at some time or another taken Benadryl®, which is an ANTI-histamine) as well as the well-known antibodies that zap very particular body invaders and the ability to adapt over time to recognize specific pathogens more efficiently.”
So how does exercise “boost” the immune system?
“Moderate exercise has been linked to a positive immune system response and a temporary boost in the production of the cells that attack bacteria (like wbcs)...there are physiological changes in the immune system as a response to exercise...immune cells circulate through the body more quickly and are better able to kill bacteria and viruses...consistent, regular exercise seems to make these changes a bit more long-lasting...when moderate exercise is repeated on a near-daily basis there is a cumulative effect that leads to a long-term immune response...those who walk [vigorously] for 40 minutes per day had half as many sick days due to colds or sore throats as those who don't exercise.”
And how does this relate to breast cancer?
“Exercise pumps up the immune system and lowers estrogen levels. With as little as four hours of exercise per week, a woman can begin to lower her risk of breast cancer.”
“You’ll be able to maintain a healthy weight. Regular exercise can help you maintain a healthy weight by building muscle and burning fat... fat cells make estrogen; extra fat cells mean more estrogen in the body and estrogen can make hormone-receptor-positive breast cancers develop and grow.”
Lastly: “Compared with the other women in the study, the women in the exercise group also boosted their number of activated T cells, made more lymphocytes, and lowered their levels of an inflammatory marker (a kind of chemical that signals parts of the body to “swell and get warm”). That data came from blood tests done after chemotherapy and at the study's midpoint and end.”
“Improvements in T cells with post-chemo exercise were also recently reported by Canadian researchers. They say they saw the benefit in a small group of postmenopausal breast cancer survivors who worked out on stationary bikes three times per week for 15 weeks.”
What are T cells? “T lymphocytes belong to a group of white blood cells known as lymphocytes, and play a central role”…when the immune system uses CELLS to attack infections. Exercise stimulates the making of these cells in the thymus part of the brain.
So – exercise boosts the immune system in several ways: helps to circulate wbcs and T cells, lowers the chemicals that cause swelling, lowers the number of fat cells which make estrogen which strengthens breast cancer cells making them harder for the immune system to fight and regular exercise keeps the immune system working like this LONGER.
Hmmm – pretty good excuse to get on those treadmills, recliner bikes, ellipticals or just go out and WALK!
Resources: http://en.wikipedia.org/wiki/Immune_system, http://sportsmedicine.about.com/od/injuryprevention/a/Ex_Immunity.htm, http://www.foxnews.com/story/0,2933,159201,00.html
Image:
http://www.perfectafrica.com/img/galleries/110/sunset-walk.jpg
