Professional athletes often push themselves to the limit in order to achieve their goals. Training often at high intensities can lead to a decline in performance.
However, a super-compensation effect occurs with the athlete showing a greater performance compared to base line when appropriate periods of recovery are provided. This is known as Functional Overreaching (FO).
If this “intensified training” is prolonged in time, the decrease in performance will become stagnant and the athlete will not be able to recover for several weeks or even months. This condition is called Non Functional Overreaching (NFO) or Overtraining (OT). When OT is ignored, it can degenerate into a chronic situation, the Overtraining Syndrome (OTS), it is not only characterized by a constant unexplainable underperformance, but is typically associated with chronic fatigue, poor sleep patterns, drop in motivation, episodes of depression, helplessness, increased sense of effort, etc.
While recovering from a FO can take as little as a week, a complete recovery from OTS can require months or even years, and in some cases it could lead to cessation of a top sports career.
If the only cause of the condition were the amount of exercise/training, the solution would be fairly simple. Unfortunately the term “syndrome” implies that the OTS is a multifactorial disorder!
Other co-stressors/triggers such as issues with family, relationship, work, school, coach, financial problems, monotony of training, excessive expectations, altitude exposure, exercise heat-stress, ongoing infections, immune depression etc., are often present.
The last two co-factors are particularly interesting. In fact infections and immune depression can be both a cause and an effect of OTS. Studies1,2 report upper respiratory tract infections due to increased training and it seems that exaggerated training could increase the duration of the so-called “immune-depression window” and the severity of the resulting outcome.It is clear at this point how difficult diagnosing and preventing OTS could be.
If the symptoms above mentioned are observable, a systematic approach is necessary. First step would be to exclude any organic and endocrinological diseases and other factors such as dietary restrictions, insufficient carbohydrate and/or protein intake, iron deficiency, or allergies.
If those are ruled out, the presence of training errors like sudden increases in volume and/or intensity, monotony of trainings, high number of competitions, end environmental stressor needs to be investigated. Additionally it is crucial at this stage looking for possible psychological and social confounding factors.
Another possibility would be the conduction of some tests for the detection of FO, NFO and OTS. 3 different solutions could be:
- Session Ratings of Perceived Exertion (sRPE) questionnaire, in which individuals subjectively estimate the overall difficulty of a workout session after its completion. sRPE has been shown3 to be a fairly useful tool for evaluating recovery across sessions;
- Measurement of Recovery Heart Rate after a submaximal test under controlled conditions. The heart rate (HR) during a submaximal exercise at self-chosen intensity should be between 85 to 90% of the maxHR4. A change in HR recovery from test to test of more than 6 bpm or a change in HR during the test of more than 3 bpm could be caused by improved training status (if positive) or accumulated fatigue (if negative)4;
- Maximal Exercise tests separated by 4 hours. A decrease in exercise time of at least 10% from one test to the other is significant5,6,7, but needs to be confirmed by specific changes in hormone concentrations such as the adrenocorticotropic hormone, prolactin (PRL) and GH6,7. In fact, in a FO stage, a less pronounced neuroendocrine response to the second exercise is found6, while in a NFO stage the response is extremely high7. With the same protocol it has been shown that athletes suffering from OTS have an extremely large increase in hormonal release in the first exercise, followed by a complete suppression in the second exercise6,7.
In conclusion, while no single marker can be evaluated for preventing or predicting OTS, the consistent monitoring of subjective, performance, biochemical, immunological, physiological, and psychological variables (through tests, questionnaires, training diaries and direct observation) can be a valid strategy to identify those athletes/individuals who are at risk of developing NFO and OTS.
Gleeson M. Immune function in sport and exercise. J Appl Physiol 1985; 103:693-699.
- Nieman DC. Immune response to heavy exertion. J Appl Physiol 1997; 82:1385-1394.
- Green JM, Yang Z, Laurent CM, Davis JK, Kerr K, Pritchett RC et al. Session RPE following interval and constant-resistance cycling in hot and cool environments. Med Sci Sports Exerc 2007; 39:2051-2057.
- Lamberts RP, Lambert MI. Day-to-day variation in heart rate at different levels of submaximal exertion: implications for monitoring training. J Strength Cond Res 2009; 23:1005-1010.
- Urhausen A, Gabriel H, Kindermann W. Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes. Med Sci Sports Exerc 1998; 30:407-414.
- Meeusen R, Piacentini MF, Busschaert B, Buyse L, De Schutter G, Stray-Gundersen J. Hormonal responses in athletes: the use of a two bout exercise protocol to detect subtle differences in (over)training status. Eur J Appl Physiol 2004; 91:140-146.
Meeusen R, Nederhof E, Buyse L, Roelands B, de Schutter G, Piacentini MF. Diagnosing overtraining in athletes using the two bout exercise protocol. Br J Sports Med 2010; 44:642-648.