Chronic fatigue and loss of performance in endurance athletes: overtraining

Summary Overtraining, a decrease in performance despite training that does not disappear after 2 weeks of relative rest, accompanied by symptoms like fatigue, anorexia, and muscle and joint pain, mood changes and feeling burnt out or stale is a frequent syndrome in endurance athletes. It is generally the result of excessive activity from training and competition in combination with insufficient rest. It can be exacerbated and/or triggered by other stresses. Excluding other illnesses its diagnosis is made on history and serial exercise test data, no simple discriminative laboratory tests exist yet. Treatment is rest and gradual reintroduction of training. Prevention is possible and can be done by carefully monitoring subjective exertion from training and general mood combined with simple exercise test results. Its aetiology is not well known. The cytokine model of excessive stress leading to a generalized inflammatory state may explain the overtraining syndrome and represents an interesting avenue of further research to improve the diagnosis and management of this frequent and debilitating health problem in athletes.