Overtraining

Reasons, Symptoms, and treatment

The overtraining syndrom can be defined as a prolonged loss of performance despite regular training sessions. The main reason for incidence of overtraining symptoms is an exceeding training load (volume and/ or intensity) or insufficient rest periods. However, the overtraining syndrome can occur without any changes in training-sessions or regeneration periods, but by psychological strain. Furthermore, nutritional reasons should be taken into consideration for diagnosis and therapy.

Besides the loss of performance, uneasiness with insomnia, difficulties in concentration, a decrease of appetite and moodiness up to depression, are common symptoms associated with the overtraining syndrome.

Due to impairments in movement-coordination, overtraining is also associated with an increased incidence of injuries.

Another important component of the overtraining syndrome is a malfunction of the immune system with recurrent viral and / or bacterial infections.

One of the underlying patho-physiological mechanisms are thought to be an exhaustion of the sympathetic nervous system, with a related decline of noradrenaline excretion (1). The resulting increased vagal tone, might serve as a protection of the organism from further loading and is associated with a decline in heart rate (2). Those symptoms should be taking into account when interpreting the FQ - as it would pretend an increase in endurance capacity despite the presence of fatigue. This underlines the importance of using different parameters (e.g. resting heart rate or own index) in the context of rating physical performance. Another common symptom is a reduced testosterone / cortisol ratio reflecting an imbalance of anabolic and catabolic processes (3).

However, since both mechanisms can only explain part of the typically observed symptoms, it is presumed that central mechanisms contribute significantly to the pathological changes. Of special interest in this context is the neuro-transmitter serotonin, as chronically depressed concentrations of this substance due to overtraining, would be able to explain most of the earlier mentioned symptoms (4).

The treatment mainly consists of rest or at least a training load reduction (intensity and volume), which is usually accompanied by a considerable improvement of symptoms. But those recommendations often fail due to the athletes or trainers unreadiness causing an unnecessary prolonged recovery time. Besides an adequate load regimen, other triggers like psychological strain, inappropriate nutrition, lack of sleep, or subclinical infections should be considered and treated sufficiently.

Reference List

(1) Lehmann MJ, Lormes W, Opitz-Gress A, Steinacker JM, Netzer N, Foster C et al. Training and overtraining: an overview and experimental results in endurance sports. J Sports Med Phys Fitness 1997; 37(1):7-17.
(2) Neumann G, Pfützner A, Berbalk A. Optimiertes Ausdauertraining. 5 ed. Aachen: Meyer & Meyer Sport; 2007.
(3) Budgett R. Fatigue and underperformance in athletes: the overtraining syndrome. Br J Sports Med 1998; 32(2):107-110.
(4) Meeusen R, Watson P, Hasegawa H, Roelands B, Piacentini MF. Brain neurotransmitters in fatigue and overtraining. Appl Physiol Nutr Metab 2007; 32(5):857-864.