Overtraining – fact or myth?

If you are serious about exercising, you have certainly been in a state of fatigue. Two-phase training and stress at work has been reflected in poor performance. However, fatigue and poor performance are a common phenomenon among athletes. Therefore, you do not have to worry, most likely you do not suffer from overtraining. It is probably an overload that occurs in athletes ranging from 5 to 60%. Overtraining syndrome is rare compared to overload and is accompanied by a complex of symptoms resulting from basic hormonal, immunological, neurological and psychological disorders. [1] [2] [3] [4]

What is overtraining?

In general, athletes train to improve their performance. They improve performance by increasing training intensity and volume. However, such a burden can only be handled if the athlete has time to periodize the workout and thus has sufficient room for rest and regeneration in his training plan. In fact, the lack of relaxation is more frequent cause of overtraining thank too many workout sessions. [1]

One of the definitions of overtraining syndrome is that it is the body’s response to excessive exercise and stress without adequate rest. This results in disorders of multiple body systems such as neurological, endocrinological and immunological functions, combined with mood changes. In some research, overtraining is described as an unexplained syndrome of underperformance. [5] [6]

Overtraining - fact or myth?

However, the exact causes of the emergence and development of this problem are not yet known, and research is still under way to further define the overtraining syndrome. However, by using the word “syndrome”, experts emphasize the multifactorial etiology of this problem, which means that excessive exercise is not the only factor of overtraining. [5]

The apparent ambiguity of overtraining syndrome is also due to the fact that clinical signs vary from individual to individual. Differences in the definition of overtraining, which cause the inconsistencies of the studies carried out so far, are also problematic. Indeed, one research suggests that up to 60% of long-distance runners show signs of overtraining during their careers. In contrast, swimmer studies show data from 3 – 30%. The authors of another study believe that if the research uses the above-mentioned overtraining definition, the likelihood of an overtraining syndrome would be much lower. This is why further overtraining studies are very much needed. [5] [9] [10] [11]

State of fatigue, overload and overtraining

However, experts distinguish 3 states that reflect the level of fatigue, overload, or overtraining. They are also referred to in the literature as expressions such as stagnation, burnout, failure or excessive revaluation of strength. The first level is functional overload, followed by non-functional overload, and the last stage is overtraining syndrome. [1]

Functional overload is a condition where excessive or intense exercising results in poor sports performance. If training reaches an individual break point, the athlete may feel overloaded, but after adequate rest and without the presence of excessive stress, his performance may improve again. This happens as a result of supercompensation, where the athlete shows higher performance compared to start points. [2]

Overtraining - fact or myth?

Although, if the athlete continues in intensive training and has no room for regeneration, there is a risk of dysfunctional overload. This may be accompanied by psychological and hormonal changes. However, in both cases of functional and non-functional overload, the athlete can fully recover, of course, after a rest period is included. [13]  

The difference between non-functional overload and overtraining syndrome lies in several factors. Overtraining accompanies a complex of symptoms resulting from basic hormonal, immunological, neurological and psychological disorders, as an organism’s response to excessive exercise and stress without regeneration. [13] [14]

Yet, the main difference between these levels is the recovery time and the impact on overall sports performance. Functional overload is a condition where your performance is weaker for a few days or weeks, but after adequate rest you are perfectly fine. The malfunctioning overload lasts for weeks to months. Overtraining is much more serious and requires long months or years of rest to restore performance. For many professional athletes, overtraining means ending a career. In the table you can clearly see the basic differences between the 3 stages of burnout. [13] [14]

Functional overloadA condition where the increase in workouts leads to a temporary weakening of performance and then to rest to improve.Days to weeksPositive, possible supercompensation
Non-functional overloadA condition where intense training leads to a longer decline in performance, but with full recovery after rest. It may be accompanied by an increase in psychological or neuroendocrinological symptoms.Weeks to monthsNegative, due to symptoms and loss of time
Overtraining syndromeState consistent with extremely dysfunctional overload, but with a longer-lasting decrease in performance, more severe symptoms, accompanied by stress. It cannot be explained by other diseases.MonthsNegative, due to symptoms and possible termination of a sports career

Signs of overtraining

Determining the difference between non-functional overload and overtraining is clinically very challenging and can often be ascertained after a complete rest period. The difference between them is mainly due to the time needed for regeneration and not the type of syndromes or their degree. However, those skilled in the art have identified some of the symptoms associated with overtraining syndrome. These include [1] :

  • tiredness
  • depression
  • bradycardia, slowing heart rhythm
  • loss of motivation
Overtraining - fact or myth?

Overtraining syndrome in anaerobic sports activities may have the following symptoms [1] :

  • insomnia
  • irritability
  • hypersensitivity
  • tachycardia, acceleration of heart rhythm
  • hypertension
  • impatience, restlessness

Other symptoms include anorexia, weight loss, lack of attention, severe and aching muscles, anxiety, or morning waking without feeling relaxed. [15] [16]

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Causes of overtraining

One approach to understanding the onset and causes of overtraining syndrome is to exclude organic diseases and factors such as calorie reduction, negative energy balance, insufficient carbohydrate and / or protein intake, iron deficiency, or allergy in combination with overtraining triggers. Possible causes of overtraining include [1] [4]:

  • increased load without adequate regeneration
  • training monotony
  • excessive number of competitions
  • sleep disorders
  • stressors, including personal life (family, relationships) and work
  • maximum exhaustion.

However, scientific evidence for the causes of overtraining syndrome is also very poor. For example, other causes, such as lack of glycogen or the presence of infection, may contribute to non-functional overload or overtraining. However, they may not be present at the time the athlete examines the doctor. There are also many reports of upper respiratory tract infections that have arisen as a result of more demanding training and have also occurred in overloaded and overtrained sportsmen. However, the amount of scientific information to support these arguments is not sufficient. [17] [18] [19]

Overtraining - fact or myth?

Prevention of overtraining syndrome

There is no one hundred percent correct test to find overtraining, and therefore there is no precise procedure for preventing this condition. However, the following methods are currently being used to monitor training and to prevent overtraining syndrome [5]:

  • retrospective questionnaires
  • training diaries
  • physiological screening
  • direct observation method

The psychological screening of the athlete and the assessment of perceived exertion are also becoming increasingly attentive to the determination of overtraining syndrome. However, you are certainly interested in what you can do to avoid annoying overload or overtraining. [20] [21] [22]

As mentioned above, there is no evidence-based precautionary measure. Experts consider screening and education of athletes as essential prevention. However, they recommend following tips [1] [23] [24]:

  • training periodization
  • adjusting the volume and intensity of the workout according to the athlete’s performance and mood
  • ensuring adequate calorie load
  • sufficient intake of carbohydrates during workout
  • enough sleep
  • promoting mental comfort
  • resting at least 6 hours between workouts
  • abstinence of training in case of illness or during periods of stress
  • avoiding extreme natural conditions
  • change of training load

Summing up this whole topic, we can state that you don’t just get overtrained by making your workouts challenging and intense. It seems that an important complex of psychological factors such as excessive coach expectations, family expectations, stress from competition, school or work combined with a lack of rest is important in the development of overtraining syndrome.

Overtraining - fact or myth?

Regular monitoring of performance and physical, biological, immune and psychological factors is the most appropriate strategy for identifying athletes who cannot cope with excessive stress from training. However, there is still a lot of research needed to answer all questions about overtraining syndrome.

However, we believe that we have helped you to orientate yourself in the issues of overtraining, fatigue and overload. Write us in the comments on how you get used to fighting the fatigue of your training, and how many days of rest you can spend a week. If you got interested in the article, do not hesitate to support it by sharing.


[1] Jeffrey B. Kreher, Jennifer B. Schwartz - Overtraining Syndrome - A practical Guide – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435910/

[2] Jeffrey B. Kreher - Diagnosis and prevention of overtraining syndrome: an opinion on education strategies – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5019445/

[3] Meeusen R, Duclos M, Gleeson M, Rietjens G, Steinacker J, Urhausen A. Prevention, diagnosis and treatment of the overtraining syndrome: ECSS Position Statement “Task Force” – https://www.tandfonline.com/doi/abs/10.1080/17461390600617717

[4] Meeusen R, Duclos M, Foster C, et al. Prevention, diagnosis, and treatment of the overtraining syndrome: joint consensus statement of the European College of Sport Science and the American College of Sports Medicine. – https://europepmc.org/abstract/med/23247672

[5] Romain Meeusen, Susan Vrijkotte, Kevin De Pauw, Maria Francesca Piacentini - Overtraining Syndrome – https://www.aspetar.com/journal/viewarticle.aspx?id=120#.XPTHxYgzY2w

[6] R. Budgett - Review of Overtraining Syndrome by British Olympic Medical Centre – https://bjsm.bmj.com/content/bjsports/24/4/231.full.pdf

[7] Romain Meeusen, Martine Duclos, Carl Foster, Andrew Fry, Michael Gleeson, David Nieman, John Raglin, Gerard Rietjens, Jurgen Steinacker, Axel Urhausen - Prevention, Diagnosis, and Treatment of the Overtraining Syndrome: Joint Consensus Statement of the European College of Sport Science and the American College of Sports Medicine – https://www.sportgeneeskunde.com/files/bestanden/Meeusen%20et%20al%202013%20Overtraining%20Consensus%20ECSS%20ACSM.PDF

[8] Phil Maffetone - The overtraining syndrome - – https://philmaffetone.com/the-overtraining-syndrome/

[9] Morgan WP, Brown DR, Raglin JS, O’Connor PJ, Ellickson KA. Psychological monitoring of overtraining and staleness. – https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1478455/

[10] Lehmann M, Foster C, Keul J. Overtraining in endurance athletes: a brief review. – https://www.ncbi.nlm.nih.gov/pubmed/8350709

[11] Hooper S, MacKinnon L, Hanrahan S. Mood states as an indication of staleness and recovery. – https://www.researchgate.net/publication/232566189_Mood_States_as_an_indication_of_staleness_and_recovery

[12] Raglin JS, Morgan WP. Development of a scale for use in monitoring training-induced distress in athletes. – https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-2007-1021025

[13] Meeusen R, Duclos M, Gleeson M, et al. Prevention, diagnosis and treatment of the overtraining syndrome: ECSS Position Statement Task Force. – https://www.tandfonline.com/doi/abs/10.1080/17461390600617717

[14] Halson SL, Jeukendrup AE - Does overtraining exist? An analysis of overreaching and overtraining research. – https://www.ncbi.nlm.nih.gov/pubmed/15571428/

[15] Nederhof E, Lemmink KA, Visscher C, Meeusen R, Mulder T. - Psychomotor speed: possibly a new marker for overtraining syndrome. – https://www.ncbi.nlm.nih.gov/pubmed/17004845/

[16] Kenttä G, Hassmén P. - Overtraining and recovery. – https://www.ncbi.nlm.nih.gov/pubmed/9739537/

[17] Rowbottom DG, Keast D, Goodman C, Morton AR. The haematological, biochemical and immunological profile of athletes suffering from the overtraining syndrome. – https://link.springer.com/article/10.1007/BF00634379

[18] Gleeson M. Immune function in sport and exercise. – https://www.physiology.org/doi/full/10.1152/japplphysiol.00008.2007

[19] Nieman DC. Immune response to heavy exertion. – https://www.ncbi.nlm.nih.gov/pubmed/913488

[20] Foster C. Monitoring training in athletes with reference to overtraining syndrome. – https://pdfs.semanticscholar.org/5962/9df5a87418e5653956d54bf8630a102544ae.pdf

[21] Kentta G, Hassmen P. Overtraining and Recovery. – https://www.researchgate.net/publication/13545392_Overtraining_and_recovery_A_conceptual_model

[22] Morgan WP, Costill DL, Flynn MG, Raglin JS, O'Connor PJ. Mood disturbance following increased training in swimmers. – https://www.ncbi.nlm.nih.gov/pubmed/3173050

[23] Armstrong LE, VanHeest JL.The unknown mechanism of the overtraining syndrome: clues from depression and psychoneuroimmunology. – https://www.ncbi.nlm.nih.gov/pubmed/11839081/

[24] Robson P. - Elucidating the unexplained underperformance syndrome in endurance athletes: the interleukin-6 hypothesis. – https://www.ncbi.nlm.nih.gov/pubmed/12895132/