Adaptations to Resistance Training (Endocrine system)

     Progressing through this current series of resistance training adaptations we have discussed the neural system, muscular, and connective tissue adaptations. Today's post will cover the hormonal responses towards resistance training. For fully disclosure, I'll briefly cover the role of the endocrine system in terms of resistance training as I've covered Testosterone, and Human Growth Hormone (HGH) in previous posts. Also, I'll be looking at the endocrine system is how it relates to resistance training.  

    Hormones are chemical messengers that are synthesized, stored and secreted into the blood by the endocrine glands. These glands can be found in multiple compartments in the body such as the brain (pituitary, hypothalamus), thyroid, liver, adrenal glands, kidneys, and sex hormones. Hormones that are released is the body's attempt to maintain homeostasis's. Binding of hormones to receptors to the body is often referred to as the lock and key theory. In this metaphor the keys would be the hormones released and the lock would be the hormone receptors. Much like locks and keys (hence the theory) a specific hormone bids with a specific receptor. Now, in some cases hormones can partially bind with another receptor or another chemical can bind with a receptor. Receptors can also be unresponsive to hormones which is called downregulation. Downregulation can be a negative aspect (think disease or illegal drugs), or it could be the muscle fiber is saturated with protein and can no longer intake additional protein. We have all heard about genetics and muscle growth. It is 100% true. Genetics play a significant factor in how swole you are going to be. This is another reason (outside of disease and drugs) that downregulation can occur. This is why the recommended dosage of protein is 20-25g every few hours. These hormones are secreted by the body before, during and after exercise in response to amount and type of stress (Anaerobic vs. Aerobic) and metabolic demands (Intensity of exercise) that exercise puts on the body. If I lift weights my body sends out hormones that can bind with the increased hormone receptors (chronic adaptation of resistance training is increased hormone receptors). Pending the intensity of the exercise the aftermath is commonly to rebuild and repair muscle tissue. Anabolic hormones are sent to signal deep inside the muscle tissue to receive additional nutrients in order to build and repair damaged tissues. This increased sensitivity of muscle tissue can be elevated for up to 24-48 hours. On the flip side catabolic or the degradation of cells can also take place. Too much exercise without proper nutrition and rest can cause an imbalance between catabolic and anabolic hormones. If that ratio tilts towards catabolic side, then overtraining may occur. Overtraining is a chemical imbalance in the body that may take weeks to months to recuperate from. This is why training plans must have rest days or at least a few light days to ensure the body has a chance to play catch up from the previous intense days. When creating or starting a new training plan pick a few days to allow the body to hormonally catch up.