Anabolic and Catabolic Hormones in Bodybuilding
There are several hormones involved in bodybuilding that contribute to muscular hypertrophy (muscle-building) and fat oxidation (fat burning). These hormones are chemical messengers released from various endocrine glands due to stimulation from the nervous system, or other hormones.
Each hormone can be classified as an anabolic (building up) hormone or catabolic (breaking down) hormone.
Growth Hormone in Bodybuilding
Growth hormone (GH) is produced in the anterior pituitary gland of the brain. This hormone is released following resistance training. Among its many functions is stimulating insulin-like growth factor (IGF) in muscles. IGF is one of the factors responsible for the division of satellite cells during the repair process.
Testosterone in BodyBuilding
Another anabolic hormone of utmost importance for hypertrophy is testosterone, which is secreted in the testes. It is one of the androgen or male hormones. Testosterone levels are elevated during resistance exercise and the hormone acts to increase protein synthesis. This allows for optimal repair of muscle fibers. In addition, it increases satellite cell count along with the number of androgen receptors in muscles, leading to greater muscle hypertrophy.
Insulin in Bodybuilding
Insulin is also an anabolic hormone capable of increasing protein synthesis. It is produced in the pancreas and it mainly functions in activating glucose uptake in cells, such as muscle cells. It can also transport amino acids, the building blocks of protein. During exercise, insulin sensitivity increases due to a muscle’s additional need for glucose. This not only enhances glucose uptake but also the uptake of amino acids, thus stimulating protein synthesis.
Glucagon in Bodybuilding
Unlike insulin, the catabolic hormone glucagon increases blood glucose levels. This hormone, also produced in the pancreas, breaks down fat to release glucose into the blood during periods when blood glucose levels are low. Low blood glucose levels may occur while performing cardio on an empty stomach.
Cortisol in Bodybuilding
Cortisol is also released when blood glucose levels are low. It is a catabolic hormone secreted by the adrenal glands (which sit on top of your kidneys) and is often referred to as the stress hormone, as stress increases cortisol levels. When secreted, cortisol converts fatty acids and amino acids into glucose. This can negatively affect hypertrophy by slowing down or even preventing protein synthesis, as the amino acids needed for this process would be converted to glucose.
Epinephrine and Norepinephrine in Bodybuilding
Two catabolic hormones that help boost performance during training are epinephrine (adrenaline) and norepinephrine (noradrenaline). These hormones, also produced in the adrenal glands, are released during exercise, especially high-intensity resistance exercise. The benefits of epinephrine and norepinephrine include increased strength, increased blood flow, and increased secretion of the anabolic hormone testosterone.
Irisin in Bodybuilding
Another hormone released during exercise is irisin. This hormone is secreted by muscles, and it converts white fat to brown fat.
White adipose tissue, or white fat, is used by the body to store energy in the form of triglycerides. This kind of fat has little mitochondria, hence its white color. Brown adipose tissue, or brown fat, is used to burn energy. Unlike white fat, it contains an abundance of mitochondria, which explains its brown color. Brown fat expends energy via non-shivering thermogenesis, and it is highly activated during cold conditions. Most people only have a small amount of brown fat in their bodies. Also, as they age, the levels of brown fat decrease. There are, however, individuals with higher amounts of brown fat than the normal population, which gives them an advantage in terms of burning calories, due to the increased thermogenesis and thus increase in metabolism.
It is possible though to increase brown fat by performing intense exercise on a regular basis. This is because intense exercise causes muscles to release the hormone irisin, helping to convert the energy-storing white fat cells to the energy-burning brown fat cells. By doing so, it causes an increase in metabolism, thus allowing your body to burn more calories.
The hormonal anabolic-catabolic balance in your body plays an important role in muscle growth and fat loss.