Overtraining Syndrome

This autonomic imbalance has been proven to stem directly from prolonged overtraining, stress, and the inability to cope. Many types of athletes suffer with Overtraining Syndrome, such as wrestlers, football players, runners, strength athletes, and world class endurance cyclists. Studies have been completed on these various groups of athletes in regards to their acute response to overtraining and overreaching periods. In some groups, researchers found acute, increased cortisol levels in overtrained athletes, while in other groups, they found acute, reduced cortisol levels in overtrained athletes; in all cases, ACTH levels remained unaffected. Overtrained athletes don’t necessarily show the same concentration of cortisol in circulation in the

In this type of overtraining, we often see a decrease in circulation of stress hormones. More often, receptors on target cells simply become desensitized to them. This leads to a state of diminished sympathetic function, predominantly brought on by a diminished amount of epinephrine β-receptors resulting from the desensitization of respective target cells. Receptor modulation occurs as a defense mechanism against the catastrophic effects of overtraining and excessive catecholamine (epinephrine and norepinephrine) release. As individuals overtrain excessively and over prolonged periods, they exhibit an increased release of catecholamines in response to the overtraining; in result, their target cells start to down-regulate as there is an unusually high amount in circulation for a long period of time. The target cells do this by desensitizing their receptors. This defense mechanism is likely due to the athlete frequently partaking in high-intensity loads, and constantly exerting maximal efforts during these loads. If an athlete’s target cells become desensitized to the circulating catecholamines, this acts as a “biological fail-safe” in which the body is attempting to halt and avert further damage from excessive physical exertion. Whether an individual is in the beginning or later stages of overtraining plays a role in the type of catecholamine release observed. In

As discussed with Overtraining Syndrome and Adrenal Insufficiency, hormone levels are varying in an abnormal fashion with respect to the adrenal glands. The hypersecretions hyposecretions of adrenal gland hormones, receptor modulation of their respective target cells, and desensitization of corresponding target cell receptors produce a vast array of ill effects on many other parts of the body. For instance, in the early stages of Overtraining Syndrome, hypersecretion of cortisol is observed. Hypersecretion of cortisol, or hypercortisolism, also causes insulin resistance as cortisol is an antagonist to insulin. This can lead to the development of Type II Diabetes Mellitus and obesity. In the more advanced stages of Overtraining Syndrome, the athlete experiences Adrenal Insufficiency, which is characterized by hyposecretion of cortisol. While Overtraining Syndrome mainly leads to secondary adrenal insufficiency, in some cases it results in primary adrenal insufficiency, or Addison’s disease. In this case, there is general damage to the adrenal cortex, which also leads to the hyposecretion of aldosterone, a crucial steroid hormone that regulates the balance of Na+ and K+ in extracellular fluid. A hyposecretion of aldosterone disrupts the homeostasis of blood pressure management and blood plasma levels. In the more advanced stages of Overtraining Syndrome, decreased levels of