Anabolic vs. Catabolic Hormones
When it comes to diet and exercise, hormones play a huge role in making someone fat, skinny, weak, strong, lean, etc. Understanding the roles and functions these hormones play in our daily lives will enable us to maximize our potential when it comes to athletic performance. This article merely serves as an introduction into the main anabolic and catabolic hormones that affect us during exercise and training. There will be more in depth coverage in later blog posts relating to these hormones.
What are Hormones?
The Oxford dictionary defines a hormone as "A regulatory substance produced in an organism and transported in tissue fluids such as blood to stimulate specific cells or tissues into action." Basically a hormone is created by an organ that send a message to prompt changes in our body. When it comes to athletic performance the main hormones of concern are anabolic and catabolic hormones.
Anabolic hormones are the hormones that build tissue. Not only do anabolic hormones build muscle, they can build fatty tissue as well. So it is important to know which hormones do what. The following is a list of the anabolic hormones and what their effect is on the tissues.
- Testosterone: This hormone is produced by the testes in males and the ovaries in females. Testosterone's main effects are a) blocking cortisol, the stress hormone, and b) stimulate protein synthesis (muscle building).
- Growth Hormone: This hormone is released by the pituitary gland and is stimulated by hunger, sleep, diet and exercise. Growth hormone promotes protein synthesis and bone and cartilage growth. Not only does it promote growth of the tissues mentioned previously, it increases the breakdown of fatty tissue as well.
- IGF-1: Short for insulin-like growth factor, this is released from various locations within your body including the pituitary gland, muscles, and liver. It is regulated by growth hormone and stimulated by muscle contractions, meaning it can be controlled, to some extent, by the intensity of muscle contractions. Like growth hormone, IGF-1 promotes growth of muscle, bone and cartilage.
- Insulin: This hormone is produced by the pancreas after consuming foods consisting of carbohydrates. Insulin has a bad reputation because of its ability to build fatty tissues which can lead to many health issues. However, it can be just as effective in building muscle as it is with fat. Whether insulin promotes protein synthesis vs. fat synthesis is largely dependent on the current state of your body. When we are sedentary and eat a high carb diet, our body will be more susceptible to fat synthesis because our fatty tissues are more insulin sensitive. If we exercise more our muscles become more insulin sensitive and even more sensitive immediately following exercise. Insulin increases protein synthesis, amino acid transport, glucose uptake and increases glycogen storage. Insulin also reduces the breakdown of muscle proteins and helps regulate the release of cortisol.
Catabolic hormones are the hormones known to break down energy sources such as glycogen, fat, and protein. People may have a knee jerk reaction to catabolic hormones as being the bad guy because when people hear the word catabolic they automatically associate it with losing muscle. Although that is true, we still need catabolic hormones to break down fat and to break down glycogen to convert to energy when necessary.
- Glucagon: This hormone is produced by the pancreas when blood glucose gets low. Glucagon's main purpose is to raise blood glucose by breaking down glycogen found in the liver and fatty tissues.
- Epinephrine: This hormone is also known as adrenaline and is produced by the adrenal gland in response to low blood glucose and resistance training. The more intense the workout, the more epinephrine is produced. Epinephrine breaks down fat, liver, and muscle glycogen but it also effects the respiratory system by increasing heart rate which pumps more blood to muscles and lungs.
- Norepinephrine: This is also produced by the adrenal gland and works in conjuction with epinephrine to breakdown fat and liver glycogen. It also helps regulate epinephrine by making sure your muscles don't burn themselves out too quickly. Norepinephrine tries to bring the body back to its normal state once your workout has ended by calming breathing and allowing other body functions like hunger and thirst to activate again.
- Cortisol: This is known as the stress hormone and it is released from the adrenal gland when blood glucose is really low. It stimulates the breakdown of fat and liver glycogen and also breaks down the protein in your muscles. Under normal circumstances your body likes to break down carbohydrates for energy first, then fat, then protein. However, when cortisol is released the order is reversed, meaning protein gets broken down for energy first. This is bad news when we talk about strength and power training because all of the hard work that is put into a workout goes to nothing. This can lead to plateau and so it is very important to try and minimize the release of cortisol.
In future posts we will go into more detail for each hormone and how we can regulate them by timing our food intake around workouts. The more you understand what these hormones do and how we can maximize their potential the more successful you will be in reaching your goals.
Chambers, A., & Kravitz, L. (n.d.). Nutrient Timing: The New Frontier in Fitness Performance. Retrieved from University of New Mexico: https://www.unm.edu/~lkravitz/Article%20folder/nutrientUNM.html
Ivy, J., & Portman, R. (2004). Nutrient Timing. Laguna Beach, California: Basic HealthPublications, Inc.
Oxford University Press. (n.d.). Hormone. Retrieved from Oxford Dictionaries: https://en.oxforddictionaries.com/definition/hormone
Schuster, S. (2011, September 17). Norepinephrine Vs. Epinephrine. Retrieved from Livestrong: http://www.livestrong.com/article/226152-norepinephrine-vs-epinephrine/
Skolnik, H., & Chernus, A. (2010). Nutrient Timing For Peak Performance. Champaign, Illinois: Human Kinetics.