The primary objective of this review is to provide an overview of how overtraining and the overtraining syndrome (OTS) affect the immune system of athletes. A secondary objective is to provide sports medicine clinicians with guidance as to how best to prevent and/or treat some of the health consequences of overtraining and the OTS as related to the development of a compromised immune system ass...

The basolateral complex of the amygdala (BLA) is critical for the acquisition and expression of Pavlovian fear conditioning in rats. Nonetheless, rats with neurotoxic BLA lesions can acquire conditional fear after overtraining (75 trials). The capacity of rats with BLA lesions to acquire fear memory may be mediated by the central nucleus of the amygdala (CEA). To examine this issue, we examined...

Habits are notoriously difficult to break and, if broken, are usually replaced by new routines. To examine the neural basis of these characteristics, we recorded spike activity in cortical and striatal habit sites as rats learned maze tasks. Overtraining induced a shift from purposeful to habitual behavior. This shift coincided with the activation of neuronal ensembles in the infralimbic neocor...

Competitive athletes are pushed routinely to the limits of their physical abilities. When tempered with periods of rest and recovery, a highly demanding training schedule can have tremendous benefits. However when an athlete is pushed too far, overtraining syndrome (OTS) can develop and result in career-ending damage. Overreaching and overtraining are part of the same spectrum that can lead to ...

Fiercer competition between athletes and a wider knowledge of optimal training regimens dramatically influence current training methods. A single training bout per day was previously considered sufficient, whereas today athletes regularly train twice a day or more. Consequently, the number of athletes who are overtraining and have insufficient rest is increasing. Positive overtraining can be re...

Weight-trained men [OT; n = 11; age = 22.0 +/- 0.9 (SE) yr] resistance trained daily at 100% one-repetition maximum (1-RM) intensity for 2 wk, resulting in 1-RM strength decrements and in an overtrained state. A control group (Con; n = 6; age = 23.7 +/- 2.4 yr) trained 1 day/wk at a low relative intensity (50% 1 RM). After 2 wk, the OT group exhibited slightly increased exercise-induced testost...

The authors have recently demonstrated that rats with basolateral amygdala (BLA) lesions acquire Pavlovian fear conditioning after overtraining. However, it is not known whether the associative basis of Pavlovian fear memory acquired by rats with BLA lesions is similar to that of intact rats. Associations are typically formed between the conditional (CS) and unconditional (US) stimuli (stimulus...

Thirteen standardbred horses were trained as follows: phase 1 (endurance training, 7 wk), phase 2 (high-intensity training, 9 wk), phase 3 (overload training, 18 wk), and phase 4 (detraining, 12 wk). In phase 3, the horses were divided into two groups: overload training (OLT) and control (C). The OLT group exercised at greater intensities, frequencies, and durations than group C. Overtraining o...

Short-term periods of increased resistance exercise training are often used by athletes to enhance performance, and can induce functional overreaching (FOR), resulting in improved physical capabilities. Non-functional (NFOR) or overtraining syndrome (OTS), occur when demand is applied for prolonged without sufficient recovery. Overtraining (OT) describes the imbalance between recovery, diminish...

Overtraining syndrome is a condition of maladapted physiology in the setting of excessive exercise without adequate rest. The exact etiology and pathogenesis are unknown and being investigated. Symptoms are multisystem in nature and often representative of underlying hormonal, immunologic, neurologic, and psychologic disturbances. Unfortunately, systematic review of the literature does not clea...