Exercise Reduces the Circulation of Female and MALE Hormones????

From the first moment my wife discovered she had breast cancer, there was a deafening silence from the men I know. Even ones whose wives, mothers or girlfriends had breast cancer seemed to have received a gag order from some Central Cancer Command and did little more than mumble about the experience. Not one to shut up for any known reason, I started this blog…

I am behind this week on all my writing. For a number of reasons. Firstly, I’m consumed by the novel I’m writing right now. Then Thursday night I had a meeting for summer school, good, but busy after a day of preparing for MAJOR testing over the next three weeks. Then a student in the school I work at unexpectedly died. Finally, Saturday was invested in the grandkids being here. So I posted Free Fiction Thursday late and now GUY’S GOTTA TALK. Sorry!

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:

6) Studies in postmenopausal women indicate that physical activity might affect postmenopausal breast cancer and endometrial cancer risk by reducing body fat, thereby lowering circulating levels of estrogens and androgens

This one, while it seems different is an iteration of the research I’ve translated above. In the interest of screening out my chit-chatting, I’ll quote the pertinent information from previous posts:

“What hormone levels does exercise reduce? Primarily estrogen. Estrogen does things besides produce secondary sexual characteristics and feed breast cancer tumors. It also increases fat stores in the body (important for energy), increases bone formation, increases triglycerides in blood, promotes fluid balances and decreases fat deposition. Exercising to a point of fat loss causes a decrease in the number of cells in women that make estrogen in fat cells (this begins in menopause) , therefore the amount of estrogen in the blood goes down and the cancer cells grow more slowly.

“Insulin and insulin-like growth factor from the pancreas and the liver respectively, regulate the uptake of glucose and fats in the body as well as regulating cell growth. With exercise, insulin absorption and effectiveness increases which shows up as less insulin in the bloodstream and doing its job in the body – which is to cause cells in the liver, muscle, and fat tissue to take up glucose from the blood and store it as glycogen rather than allowing it to float around the bloodstream – which is toxic.” (from – Exercise Reduces Estrogen)

“The fat cells are where the leptin is manufactured, therefore, when you bomb the factories with walking, eating sensible amounts and kinds of food, using your elliptical machine, parking farther out in a parking lot and walking in and taking the Pup for a quick walk to the park; you reduce the amount of leptin in your blood because you have fewer fat cells to make it!” (from – Exercise Reduces Leptin)

“In other words, the more you exercise, the more fat is metabolized (duh!); but the more you exercise, the LESS these hormones work (huh?); but because of exercise, you don’t need as MUCH of the hormone to do the work of fat destruction (“lipolytic activity”); therefore, there are fewer hormones to drive cancer cell growth. (The last sentence is a layman’s interpretation of everything I’ve read. I’m NOT a doctor. I am a biology major and I’ve read constantly and regularly both popular and scientific articles. None of the articles says this outright – but I believe that it is implied.)” (from – Exercise Reduces Metabolic Hormones)

“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.” (from – Exercise May Improve Immune Functions)

Lastly: ANDROGENS??? Aren’t those “male hormones”?

Yes. Like testosterone.

So: “The role of endogenous steroid hormones in pre- and post-menopausal breast cancer has been investigated in EPIC in the largest studies conducted to date on this topic. We have shown that both estrogens and androgens increase breast cancer risk while SHBG decreases risk after menopause. In parallel, overweight and low physical activity increase breast cancer risk after menopause. On the contrary, before menopause, androgens increase breast cancer risk, progesterones decrease risk and SHBG and obesity are not associated with risk. These findings provide strong clues for further investigations of the metabolic and hormonal factors specifically related to pre- and post-menopausal breast cancer…[as a side note] We found that the consumption of fruit and vegetables is not associated with breast cancer risk. This is an important finding as it helps to narrow down the factors potentially involved in breast cancer etiology and prevention.” (from – see source below in Resources)

I know this entry is more summary than translation – but at this point, I thought it safer to NOT reinvent the wheel and start all over again!

Resources: http://epic.iarc.fr/keyfindings.php
Image: http://upload.wikimedia.org/wikipedia/commons/thumb/5/5d/Testosterone-from-xtal-3D-balls.png/200px-Testosterone-from-xtal-3D-balls.png