Exercise Reduces Metabolic Hormones and Inflammation! (HUH?)

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…

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:

4) Physical activity may decrease risk for various cancers by several mechanisms including reducing metabolic hormones and inflammation

First of all, what are metabolic hormones?

Let’s back up and start fresh. What is metabolism?

Metabolism is the collection of chemical reactions that happen in the cells of the body that sustain life – things like growth, reproduction, structure maintenance, and response to the body’s environment. These reactions are controlled by things inside the cells and things outside of the cells.

Hormones come from outside the cell and are “messengers” that travel through the blood and attach themselves to specific landing sites on the outside of a cell then pass their “message” into the cell.

Among the hormones that control the metabolism of cells are Insulin (controls glucose or sugar uptake); Thyroxine and Triiodothyroxin (controls the basal metabolism rate [BMR] – what we’d call the “resting state” of the body);Growth Hormone (obvious); Cortisol (stimulates the making of sugars and causes a decrease in sugar uptake); Estradiol (has a complex job in that it controls female body structure, protein synthesis, blood coagulation, and the amount of LDL and HDL fat in the blood).

“…exercise is one of the major links between the hormonal modulators of energy intake and output. [These hormones] directly affect adipose metabolism and metabolic hormones that influence adipose metabolism. Acute low- and moderate-intensity exercise causes hormonal changes that facilitate lipolytic activity. Exercise training reduces these hormonal responses, but the sensitivity to these hormones increases so that lipolysis may be facilitated.”

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.)

How about the inflammation?

Inflammation is part of an extremely complex reaction in the human body basically aimed at removing some sort of damaging event so it can start healing. In the human body, inflammation is caused by vasoactive amines, eicosinoids, cytokines (antiviral, immunoregulatory, and anti-tumor properties), growth factors, reactive oxygen species and hydrolytic enzymes.

“Inflammation orchestrates the microenvironment around tumors, contributing to proliferation, survival and migration. Cancer cells use selectins, chemokines and their receptors for invasion, migration and metastasis. On the other hand, many cells of the immune system contribute to cancer immunology, suppressing cancer.”

Regular physical activity is reported to decrease markers of inflammation although the correlation is imperfect and seems to reveal differing results contingent upon training intensity…long-term chronic training may help reduce chronic low-grade inflammation…low-intensity training can reduce resting pro-inflammatory markers (CRP, IL-6), while moderate-intensity training has milder and less-established anti-inflammatory benefits.”

Therefore exercise, while it is NOT a miraculous cure for breast cancer CERTAINLY has the following positive effects on lowering metabolic hormones and inflammation:

• more fat is metabolized

• you don’t need as MUCH of the hormone to do the work of fat destruction

• fewer hormones to drive cancer cell growth

• decrease markers of inflammation
Resources: http://en.wikipedia.org/wiki/List_of_human_hormones, http://www.ncbi.nlm.nih.gov/pubmed/15896089 , http://en.wikipedia.org/wiki/Inflammation
Image: http://i.usatoday.net/tech/_photos/2010/03/08/fat-cellx.jpg