Overtraining SyndromeOvertrainingSyndrome:R.Budgett particularly in the Eastern bloc35. This involves a reduction in all stresses with rest, sleep, relaxation therapyandcounsellingaswellas

Br. J. Sp. Med; Vol. 24, No. 4

Review

Overtraining SyndromeR. Budgett, MBBS, MA, Dip Sports Med, MRCGPThe British Olympic Medical Centre

This review discusses the overtraining syndrome which ischaracterized by fatigue and underperformance precipi-tated by stress of training. Other stresses, depression andan increased susceptibility to infections may be important.Treatment requires rest and a stress management programover 3 months.

Keywords: Stress, underperformance, overtraining syn-drome, staleness, chronic fatigue

IntroductionThere have been numerous anecdotal reports ofathletes underperforming for no apparent reason andtaking weeks to recover form. The term 'overtrainingsyndrome' is often used to describe these athletessuffering from prolonged fatigue. This term impliescausation, but there is no firm evidence for this, andathletes who complain of fatigue and underperform-ance may not all be suffering from a singlepathophysiological entity.Other terms such as 'burnout', 'staleness', and

'chronic fatigue syndrome' have been used todescribe a similar picture. Some commentators feelthe problem is post-viral in origin linking it with ME1.The picture is complicated by a growing number ofreports of immune dysfunction after prolongedexhaustive training, so that frequent or prolongedinfections causing fatigue and malaise may besecondary to overtraining rather than the primarycause of the problem.

DefinitionsFatigueThis is a subjective condition synonymous withtiredness, lethargy and listlessness, with symptomssuch as poor concentration and poor tolerance ofactivity. It contrasts with physiological fatigue whichcan be defined as the failure to sustain an expected orrequired muscular force. The mechanism depends onthe duration of exercise, so that a sprinter willbecome fatigued in seconds in association with high

Address for correspondence: Dr R. Budgett, The British OlympicCentre, Northwick Park Hospital, Watford road, Harrow,Middlesex HA1 3UJ, UK© 1990 Butterworth-Heinemann Ltd0306-3674/90/040231-06

lactate levels, while a marathon runner will fatigueafter nearly 2 hours due to glycogen depletion3.Fatigue in this review refers to the subjectivecondition.

Overtraining syndrome1. This may be seen as prolonged fatigue andunderperformance, following a period of heavytraining or competition, lasting at least two weeksand confirmed on an appropriate ergometer, or bycomparing training times or results in previouscompetition. Identifiable medical illness must havebeen excluded. This assumes that the stress oftraining is the major factor in the aetiology ofprolonged fatigue in athletes.

2. Athletes who suffer recurrent infections duringperiods of maximum training or competition stressmay suffer from overtraining syndrome.

This assumes that overtraining is the major stresscausing immune dysfunction, producing increasedvulnerability to infection.

Burnout/stalenessThe definition is as for 1. in the overtrainingsyndrome. It is often used to describe swimmers

Chronic fatigue syndromeThis is the same definition as 1. in the overtrainix~gsyndrome. The term is used in American literature6'

Post-viral infection/METhis causes fatigue lasting many months following aviral, possibly enteroviral, infection8. Patients areunable to function in normal life let alone train. Fewathletes fall into this category. There is no evidencethat the proposed reduction in immune function inovertrained athletes predisposes to post-viral fatigue,so this cannot yet be defined as part of theovertraining syndrome.

Sympathetic and parasympathetic stalenessThese terms have been used to sub-divide theovertraining syndrome, but are not generally usednow due to the lack of evidence for a separateparasympathetic type which was supposedly char-acterized by hypoglycaemia during exercise and

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Overtraining Syndrome: R. Budgett

exhaustion of the neuro-endocrine system. Thesympathetic type was defined as essentially aresponse to prolonged stress and fits with overtrain-ing definition 1.9r

Over-reachingPurposeful overtraining may be part of a plannedprogramme in order to stimulate adaptation. This isfollowed by a period of relative rest or tapering inorder to allow full supercompensation, normallywithin 1-2 weeks'2.

Clinical pictureAs suggested by the two definitions, there are twobroad clinical presentations which may overlap.

Athletes may suffer from fatigue and a perform-ance slump which does not improve despite restingover 2 days or reducing the training load for 2 weeks.They are often highly motivated, conscientiousindividuals who have responded to their lack of formby increasing the training load, leadin to a viciouscycle of fatigue and underperformance .

Others have been entering a series of hardcompetitions, often with initial success, but thenbegin to become tired and produce steadily worseresults'3. These athletes are characterized by theirreluctance to stop or reduce their level of training andcompetition due to their own ambition and determi-nation sometimes combined with pressure from thecoach, fellow athletes and parents.Other elite competitors build up their training for

two to three months, reaching a high level ofperformance, but then suffer from a viral infectionwhich stops them in their tracks. This often occursaround the time of a major competition or series ofraces. After enforced rest for 1-2 weeks they restarttraining, but when they reach a certain level againbreak down and the cycle repeats itself'4' 15. As yet,there is only indirect evidence of immune dysfunc-tion (Riddell: personal communication).

Reports of athletes presenting in this way arenearly all anecdotal, but the constant flow of reportsfrom coaches and athletes show that they perceivethere is -a problem despite the fact that it is poorlydefined'2. A large number of symptoms and signshave been described, but some of them relate toathletes who are only over-reaching, and others mayrepresent underlying unidentified disease since theyare inconsistently reported in different studies. Thereis no accepted gold standard for the diagnosis of theso called overtraining syndrome.

SymptomsAthletes can only be labelled as overtrained if theyare fatigued and underperforming. They may com-plain of fatigue at rest, with a loss of purpose, energyand competitive drive'6 17'. Feelings of helplessness,incompetence, being trapped in a routine, andemotional lability and loss of libido have beendescribedl'' 13. Athletes often admit to increased

anxiety and depression (90%), irritability (70%) andsleep problems (90%) including difficulty getting tosleep, nightmares and waking in the night'8. Loss ofappetite, weight loss, heavy painful muscles andexcessive sweating have been reported4' 11, 13Athletes have also been noted to complain of anincreased susceptibility to infections2"16 (Riddell:personal communication) and injuries'9.

SignsThere are no physical signs consistently associatedwith the overtraining syndrome. The following havebeen reported in association: raised early morningheart rate, increased postural drop in blood pressureand rise in heart rate, and a slow return of pulse rateto normal after exercise20' 21, decreased maximallactate levels during exercise and decreased maximalpower output'0. There may be lymphadenopathy,diarrhoea, increased susceptibility to allergies andminor scratches may heal slowly'3 (Riddell: personalcommunication). However, none of these signs arereliable indicators of the syndrome, since they canappear during periods of over-reaching without anydrop in performance. They are reported inconsistent-ly and some may represent underlying disease.

Precipitating factorsPhysical stressStresses other than those of hard training andcompetition may lead to an inability to recover from apreviously well tolerated training programme.Glycogen depletion leads to rapid fatigue particu-

larly after the anaerobic threshold is reached, andmay predispose to more prolonged fatigue22. Thus, apoor diet with insufficient carbohydrates to meettraining demands23, as may occur when an athlete isattempting to lose weight, will increase the difficultyin coping with a particular programme.Dehydration will also increase the perceived stress

of exercise and is a potent cause of underperform-24ance

Infections, as well as being reported more frequent-ly in hard training, will make it more difficult forathletes to tolerate the load.

Psychological stressThe profile of mood states questionnaire askingathletes to rate their current feelings or mood againsta list of 65 words has been used to follow them intraining. It shows reduced vigour and increasedtension, depression, anger, fatigue and confusion(inverted iceberg profile) during periods of heavytraining2' 26. This is even worse in those athletes whosuffer from prolonged fatigue and are labelled as staleor overtrained27 . It has been suggested thatacademic, economic and social stressors may beimportant. They certainly feature prominently inanecdotal reports. However, there is no goodevidence for their role due to the lack of studies oncompetitors who become overtrained.

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Differential diagnosisSerious diseaseThis is fortunately rare but it is important to exdudeviral myocarditis or arrhythmias, bearing in mindthat electrocardiograms are often abnormal, particu-larly at rest, in highly trained athletes29.

Glycogen depletionProlonged inadequate carbohydrate intake may causeprolonged fatigue as well as precipitating a trueovertraining syndrome.

AnaemiaIt is important to distinguish between true anaemiawhich may be due to iron deficiency, particularly infemale athletes', and the physiological reduction inhaemoglobin due to increased plasma volume whichhas no effect on performance. Low iron stores asmeasured by serum ferritin levels were thought to beresponsible for many cases of underperformance31,but it has been shown that levels as low as 12 ng/mlare not associated with underperformance. There isno advantage in raising this with iron supplements32.

Exercise induced asthmaThis diagnosis is easily missed unless enquired fordirectly, and is a common cause of apparent recurrentcolds and underperformancem. A 15% or greater fallin peak expiratory flow rate or FEV1 after exercise isconsidered diagnosticTM.

Physical changes due to ageThese are sometimes difficult to accept! The change inshape of female athletes, such as gymnasts orswimmers, at menarche is particularly dramatic ifthey have a few months off and put on weight. Thiswill greatly affect performance but should not causefatigue (P. Garret: personal communication).

PsychologicalThere is a psychological element to every athlete'sunderperformance, but in some this is of overridingimportance so that the training stress is irrelevant. Inthese cases the athlete cannot be labelled asovertrained, and psychological help is far moreimportant than rest from training.

PreventionIt is obviously important to avoid the precipitatingfactors discussed earlier, but early detection and acarefully designed training programme may also playa role in prevention.

Early detectionThe careful monitoring of athletes who are over-reaching has been suggested in order to pick up trueovertraining or staleness in the early stages21. In


general, the longer the history of fatigue beforetraining is stopped, the longer recovery takes12. Thedrop in performance often become obvious too late toavoid a prolonged period of fatigue. Because of this,early morning heart rate20 and mood state question-naires27 have been used. Others have suggestedusing serial measurements of haemoglobin, haema-tocrit or creatine kinase. Unfortunately, these testsare non-specific and reflect training load or may noteven change at all'0 16. Thus, there is no objectiveearly screen that can be reliably used to detect thoseathletes who will become overtrained during a periodof overreaching.

TraimngThere is consensus that undertraining is better thanovertraining, and this seems to be the surest way ofavoiding prolonged fatigue21. However, maximaltraining is needed for an athlete to reach their fullpotential and various strategies have been suggestedto allow this while minimizing the risk of theovertraining syndrome. Sudden increases in trainingload should be avoided, a steady increase of 5% perweek being optimal for most athletes. Intensiveexercise with short rests and frequent competition isdangerous. Monotonous training should also beavoided, particularly in swimmers11. Notice shouldbe taken of other stresses, both physical andpsychological, since these may combine and exceedan individual's ability to adapt. Training should bereduced at these times9.

ManagementRestCases need to be assessed individually, and it is oftendifficult to persuade athletes that they need to rest.However, this seems to be the basis of treatmentsince an improvement in performance has beenshown after 3-5 weeks rest, despite the fact thatthese athletes must become detrained in this time2.The build up to full training may take up to threefurther months. It is thought important to avoidcompetition13, although individuals may producepersonal best performances 'out of the blue' beforeapparent complete recovery6.

In the majority of athletes who are still able to workand function in normal life, a regime of relative resthas been suggested using gentle non-competitiveexercise often in a different sport with no measure ofperformance available. Usually this low level ofexercise is easily tolerated and the psychological andphysical benefits will help speed recoveryR, whilemaintaining a degree of cardiovascular fitness. Theemphasis should be on exercise as a therapeutic toolto speed rehabilitation, rather than as a means toobtain a training effect which is what the athletes areused to.

RegenerationNo controlled trials of treatment have been reported,but regeneration strategies have been widely used

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particularly in the Eastern bloc35. This involves areduction in all stresses with rest, sleep, relaxationtherapy and counselling as well as saunas, massage,hydrotherapy and physiotherapy5. Nutrition islooked at in detail and vitamins and other supple-ments given routinely although there is no provenbenefit. Psychotherapy and counselling have beenused in the USA to successfully treat underperform-ing athletes diagnosed as stale and depressed25, butthere are no reports on the use of antidepressants.However, there is one report of anabolic steroid usein an attempt to speed recovery-,, and no doubtothers have tried this unproven and illegal tacticwithout reporting their results. Our own anecdotalobservation suggests that recovery takes three toeight weeks. However, there is a danger of relapse ataround 3 months. We advise reduced training andcompetition stress for up to 4 months.

Investigating the overtraining syndromeThere are only a few studies of truly overtrained elitecompetitors18 25'27' 28,37 (Riddell: personal communi-cation). Most investigators have concentrated onstudying the response to severe exhaustive exercisein an attempnt to find markers of and mechanisms toexplain the overtraining syndrome. This ignores thepreviously discussed problem that overtrained com-petitors may be training no harder than their peers,and that it is something unique to that individual thatcauses prolonged breakdown with failure to adapt orbenefit from training. Moreover, in those studies inwhich performance is monitored, there is generally aquick recovery or even an improvement at the end ofthe period of extreme over-reachinge.Routine tests as markersHaemoglobin and haematocrit have been shown tofall during periods of heavy training39, but this isprobably physiological, and does not correlate withperformance. Others have found no change'6. ECGsare often abnormal in fit athletes and are no differentduring periods of heavy training or underperform-ance

Creatine kinase has been used by many resear-chers, but unfortunately has been shown to rise inproportion to training load, presumably due tomuscle damage, does not correlate with performance,and there is wide individual variability (50 fold)'3'20.In a single study, thyroxine and TSH were reducedduring a period of prolonged physical and mentalstress, but levels did not correlate with performanceand recovery took only two days.

Hormonal and endocrine changesCortisol is catabolic, helping to mobilize glycogen andfree fatty acids, and rises after hard exercise as part ofthe stress hormone responses40' 4. Psychologicalstress also raises levels, particularly before competi-tion42. Testosterone has also been shown to rise inresponse to exericse, and there is evidence that levelsare higher in well trained individuals'7'43 44.

Intense and prolonged training will raise cortisollevels even higher, but will reduce testosterone47.Thus, it has been suggested that hormonal changesare involved in or at least are markers of theovertraining syndrome'7. It may be that at a criticaltestosterone/cortisol ratio the predominance of cata-bolism over anabolism means that an athlete isunable to recover from training, and continues tobreak down rather than adapting positively.Harkonnen et al. looked at 15 long distance

runners, and increased the training load of nine ofthem for just one week48. The testosterone/cortisolratio fell in eight of the nine who were dassified asovertrained and in only one control. There was norecord of chronic fatigue or underperformance. Theseathletes were therefore not truly overtrained, butmerely exhibited a normal response to extremetraining stress.O'Connor et al. followed salivary cortisol levels in

14 female swimmers over 6 months27. As well as theexpected rise in baseline levels as training increasedfrom 2,000 to 12,000 yards per day, they foundsignificantly higher levels in those suffering fromstaleness and underperformance compared to thosemaintaining their performance. This correlated withdepressed mood state27.Barron and Noakes in 1985 suggested that the

overtraining syndrome was due to hypothalamic-pituitary dysfunction37, as may be the case in femaleathletes who develop amenorrhoea. They found asignificantly reduced hormonal response to insulininduced hypoglycaemia in four chronically fatiguedand underperforming athletes compared to controls.However, basal cortisol levels were raised, makingthe interpretation of the results difficult, but furthersupporting the existence of high basal cortisol levelsin overtrained athletes. Testosterone was not mea-sured.

Mood stateSome commentators feel that the chronic fatigue seenin athletes is 'depression with a new face7'. It ispossible that the stress of heavy training andcompetition, combined with other stresses, canprecipitate depression. This would certainly explainwhy some athletes are more susceptable to the socalled overtraining syndrome than others. There is nodoubt that the athletes are depressed with changes inglobal mood as measured by the Profile of MoodStates (POMS) questionnaire 28.The symptoms of overtraining are very similar to

those described in depression with psychomotor andphysiological retardation, chronic fatigue, depressedappetite, weight loss, insomnia, musde soreness,and tension and depression. However, the moodstate changes in response to an increased trainingload are non-specific, with a decrease in vigour andincrease in tension, depression, anger, vigour andconfusion in all athletes, so it is difficult to use amood state questionnaire to predict or diagnose theovertraining syndrome. Despite this, there is evi-dence that this change is even greater in underper-forming athletes27 and so may potentially be used to




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support the diagnosis and monitor recovery sincemood state improves with rest in parallel withperformances.

Immune functionAnecdotal reports have linked susceptibility toinfections to periods of heavy training, sometimesassociated with prolonged fatigue and underperform-ance'145 (Riddell: personal communication).Many studies have investigated the effect of

exercise on the immune system, and it is nowaccepted that there is a release of white blood cellscausing a temporary leucocytosis after heavy exer-cise2. However, there is no evidence that this offunctional significance.Some studies have shown a reduced T helper: T

suppressor cell ratio after hard exercise49',', but thisdid not correlate with temporary suppression oflymphocyte function which has also been de-scribed51. Makinnon showed reduced salivary IgAand 1gM concentrations and reduced NK cell activityafter one to two hours of heavy exercise52. However,these changes resolved soon after exercise, and arenot found consistently. Nash showed that trainingenhanced immune function-3. Thus, there is stilluncertainty about the effect of exercise and trainingon immune function which may depend on thepre-existing state of the athlete, and the type ofexercise.

It is difficult to isolate the effect of psychologicalstress which has been shown to be capable ofsuppressing immunity2 maybe by raising cortisollevelsTM, although immunosuppression may occur inadrenalectomized animals5.Another explanation for the widely reported, but

as yet unproven, susceptibility of athletes to infec-tions during periods of chronic fatigue and underper-formance, is through the reduced plasma glutaminelevels which have been found in overtrainedathletes"8. This amino-acid is produced in musclefrom the breakdown of other amino-acids56, and is anessential fuel for all rapidly dividing cells57. It donatesnitrogen for purine synthesis, as well as beingoxidized to provide energy. It also provides 35% ofthe energy for lymphocyte metabolism5. Thus, lowplasma levels may cause immunosuppression, lead-ing to frequent infections and a worsening cycle ofunderperformance.

VirologyIt has been suggested that the majority of cases ofchronic fatigue in athletes are post-viral in origin'.Infectious mononucleosus is a well known cause ofchronic fatigue, and there have been cases of proveninfection with enteroviruses and coxsackie B18, butthe relevance of high titres to underperformance hasbeen questioned. Subclinical infection or high titresdid not correlate with objective or subjective under-performance in a group of 698 athletes'5. In anotherstudy of 12 fatigued athietes, there were two positivemonospots with atypical mononudlear cells (glandu-lar fever), and two raised coxsackie B titres. However,no cause was found in the other eight59.

If a definite viral cause is found, then a diagnosis ofthe overtraining syndrome cannot be made unless itis part of a pattern of recurrent infections at times ofheavy training and competition stress. However,high viral titres have to be interpreted in their clinicalcontext, and may be an incidental finding in fatiguedcompetitors.

ConclusionCurrent evidence on the pathophysiology of theovertraining syndrome is limited, but there is nodoubt that the problem of unexplained underper-formance does exist.

Investigators have suggested hormonal, psycholo-gical, immunological and post-viral aetiologies, and itis possible that all these play a part in differentathletes. Increased catabolism, depression, infec-tions, and the stress of training combined with otherstresses, may all lead to fatigue and underperform-ance. The stress of training can cause depression,raised cortisol levels and reduced plasma glutaminelevels which may all contribute to decreased immunefunction.Management consists of rest and stress reduction

through a regeneration programme includingcounselling and relaxation therapy. Recovery takesthree to eight weeks.

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Overtraining SyndromeOvertrainingSyndrome:R.Budgett particularly in the Eastern bloc35. This involves a reduction in all stresses with rest, sleep, relaxation therapyandcounsellingaswellas