Exercise Reduces Leptin Levels!

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

2) A home-based physical activity program had a beneficial effect on the fitness and psychological well-being of previously sedentary women who had completed treatment for early-stage through stage II breast cancer. Increasing physical activity may influence insulin and leptin levels and influence breast cancer prognosis.

As “psychological well-being” isn’t really something scientists can QUANTIFY (quantify means to put numbers to something, as in measuring the HbA1c levels in the blood of a diabetic) and while they can QUALIFY it (“I feel so much more alive when I exercise!”) and it’s a perfectly valid measure of health, I’m going to skip over it in this analysis because different things make different people happy on different days.

I looked at how exercising can have a profound impact on insulin and insulin-like hormone last week, so we’ve been there already.

But what are “leptin levels” and why do they matter in breast cancer – and should they be going up or down?
Leptin is a hormone, like insulin, but it is made in the white fat tissue of a human body rather than in the pancreas. The amount of leptin in the blood is proportional to how much body fat a person has. Like all hormones, leptin has a purpose in the body. It travels to the brain where it finds its place in receptors in brain neurons where it is involved in regulating energy intake and expenditure.

What’s important HERE is that leptin controls food intake and energy expenditure. But what does that have to do with breast cancer?

According to some fairly technical abstracts I read (I have a BS in biology and I’ve been teaching, reading and going to conferences for 31 years; I can read “scientese”) leptin causes its target cells to have more receptors to particular hormones (for those of you who want to check it out, Google “leptin upregulation”). In this case, estrogen – and it is estrogen that initiates and continues the growth of breast cancer cells. That’s why after chemotherapy my wife has to continue to take estrogen-suppression tablets for five years.

Exercise then, apparently affects the levels of leptin – but it AIN’T a magic bullet, folks, so don’t go asking your doctor for leptin injections! The reason that leptin levels go down with exercise is because you LOSE WEIGHT and FAT! 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!

So WALK people!

Original Essay: http://breastcancerreaper.blogspot.com/2012/03/exercise-how-freak-is-it-miraculous.html

Image: http://www.rkm.com.au/cell/cellimages/fat-cells-adipocytes.jpg