Endocrinology - It's What's Happening!

by Kris Pitcher

When we spoke about nutrient timing I said our hormonal environment was primed for progress. I thought it might be a good idea (aka super exciting in a geeky fashion) to talk about what those hormones are and what their role is. Get your pencil pocket protectors out! We're heading to endocrinology 101!

Hormones are chemical messages which effect our cells. They tell our bodies to do certain things. There are hormones which effect our sexual function, reproduction, our mood, metabolism, and our growth & development. We're going to talk about the last two.

Metabolism and growth and development will be the topic for the day as it relates to exercise. Further, we can break those out into two categories; catabolic, and anabolic. And just to refresh our memories: catabolism means breaking down in metabolism; anabolism means building up or synthesizing in metabolism.

Let's look at the hormone, it's exercise response, and it's function in the body. Here we go! Our catabolic hormones include epinephrine, which increases with moderate to intense exercise. It's job is to increase glycogen breakdown (think catabolic metabolism, we are breaking down stored nutrients - glycogen - for use). Next is norepinephrine, it also increases with moderate to intense exercise. Norepinephrine increases our fat breakdown, increases our heart rate response and our glycogen breakdown.

Two more to go in our catabolic category. Glucagon which increases with prolonged exercise. It's job is to increase gluconeogenisis. Big word, but when we break it down it's easy. Gluconeogenisis is the formation of glucose from noncarbohydrate sources - meaning amino acids. Remember your latin class? Gluco (glucose), neo (new), genisis (begining)...big easy word. The last hormone in this category is cortisol. Cortisol increases with intense prolonged exercise (it also increases with stress). It decreases glucose uptake and promotes fatty acid breakdown.

You're doing great! Did you know there was so much going on in your body when you were exercising? Let's look at the next group, the anabolic hormones. Recall anabolic means building or synthesizing in metabolism. Let's build!

Insulin is a hormone we've all heard of. It decreases with exercise and it's job is to increase glucose, amino acids and fatty acid uptake. Testosterone is next which increases with exercise. It controls muscle size, increases red blood cells and decreases body fat. Don't worry ladies. you're body won't just make more because you start exercising. As you know, we have limited levels compared to men.

Growth hormone is next which increases with exercise response. It's role is to stimulate testosterone, mobilize fatty acid for energy, decrease glucose uptake, and increase gluconeogenisis. You can see hormones work together to get things done. IGF-1, or insulin growth factor 1 is stimulated by growth hormone and it's role is to stimulate growth.

Ok, there isn't a pop quiz! But you can see there is a lot going on in your body hormonally in response to exercise and knowing there are hormones that break cells down and build cells up through the process of metabolism is just important knowledge for you to be aware of.

Being informed helps you know why it's important to eat when you need to eat, exercise, get adequate rest etc. If it sparks an interest I hope you'll seek more information. If it gets you to make sure you get your post-workout meal within 30 minutes...well I'll just feel all warm inside!