Abstract
Athletes experience minor fatigue and acute reductions in performance as a consequence of the normal training process. When the balance between training stress and recovery is disproportionate, it is thought that overreaching and possibly overtraining may develop. However, the majority of research that has been conducted in this area has investigated overreached and not overtrained athletes. Overreaching occurs as a result of intensified training and is often considered a normal outcome for elite athletes due to the relatively short time needed for recovery (approximately 2 weeks) and the possibility of a supercompensatory effect. As the time needed to recover from the overtraining syndrome is considered to be much longer (months to years), it may not be appropriate to compare the two states. It is presently not possible to discern acute fatigue and decreased performance experienced from isolated training sessions, from the states of overreaching and overtraining. This is partially the result of a lack of diagnostic tools, variability of results of research studies, a lack of well controlled studies and individual responses to training.
The general lack of research in the area in combination with very few well controlled investigations means that it is very difficult to gain insight into the incidence, markers and possible causes of overtraining. There is currently no evidence aside from anecdotal information to suggest that overreaching precedes overtraining and that symptoms of overtraining are more severe than overreaching. It is indeed possible that the two states show different defining characteristics and the overtraining continuum may be an oversimplification. Critical analysis of relevant research suggests that overreaching and overtraining investigations should be interpreted with caution before recommendations for markers of overreaching and overtraining can be proposed. Systematically controlled and monitored studies are needed to determine if overtraining is distinguishable from overreaching, what the best indicators of these states are and the underlying mechanisms that cause fatigue and performance decrements. The available scientific and anecdotal evidence supports the existence of the overtraining syndrome; however, more research is required to state with certainty that the syndrome exists.
Similar content being viewed by others
References
Urhausen A, Kindermann W. Diagnosis of overtraining: what tools do we have? Sports Med 2002; 32(2): 95–102
Halson SL, Bridge MW, Meeusen R, et al. Time course of performance changes and fatigue markers during intensified training in trained cyclists. J Appl Physiol 2002; 93(3): 947–56
Jeukendrup AE, Hesselink MK, Snyder AC, et al. Physiological changes in male competitive cyclists after two weeks of intensified training. Int J Sports Med 1992; 13(7): 534–41
Kreider R, Fry AC, O’Toole M. Overtraining in sport: terms, definitions, and prevalence. In: Kreider R, Fry AC, O’Toole M, editors. Overtraining in sport. Champaign (IL): Human Kinetics, 1998: vii–ix
Rowbottom DG, Keast D, Morton AR. Monitoring and prevention of overreaching and overtraining in endurance athletes. In: Kreider R, Fry A, O’Toole M, editors. Overtraining in sport. Champaign (IL): Human Kinetics, 1998: 47–66
Fry RW, Morton AR, Keast D. Overtraining in athletes: an update. Sports Med 1991; 12(1): 32–65
O’Toole ML. Overreaching and overtraining in endurance athletes. In: Kreider R, Fry A, O’Toole M, editors. Overtraining in sport. Champaign (IL): Human Kinetics,1998: 3–17
Israel S. Problems of overtraining from an internal medical and performance physiological standpoint. Med Sport 1976; 16: 1–12
Lehmann M, Foster C, Dickhuth HH, et al. Autonomic imbalance hypothesis and overtraining syndrome. Med Sci Sports Exerc 1998; 30(7): 1140–5
Kuipers H, Keizer HA. Overtraining in elite athletes: review and directions for the future. Sports Med 1988; 6(2): 79–92
Lehmann MJ, Lormes W, Opitz-Gress A, et al. Training and overtraining: an overview and experimental results in endurance sports. J Sports Med Phys Fitness 1997; 37(1): 7–17
Lehmann M, Foster C, Keul J. Overtraining in endurance athletes: a brief review. Med Sci Sports Exerc 1993; 25(7): 854–62
Selye H. The stress of life. New York: McGraw Hill, 1976
Rushall BS. A tool for measuring stress tolerance in elite athletes. J Appl Sport Psychol 1990; 2(1): 51–66
Morgan WP, Brown DR, Raglin JS, et al. Psychological monitoring of overtraining and staleness. Br J Sports Med 1987; 21(3): 107–14
O’Connor PJ, Morgan WP, Raglin JS, et al. Mood state and salivary cortisol levels following overtraining in female swimmers. Psychoneuroendocrinology 1989; 14(4): 303–10
Hooper S, MacKinnon LT, Hanrahan S. Mood states as an indication of staleness and recovery. Int J Sport Psychol 1997; 28: 1–12
Raglin JS, Morgan WP. Development of a scale for use in monitoring training-induced distress in athletes. Int J Sports Med 1994; 15(2): 84–8
Koutedakis Y, Sharp NC. Seasonal variations of injury and overtraining in elite athletes. Clin J Sport Med 1998; 8(1): 18–21
Fry RW, Morton AR, Garcia-Webb P, et al. Biological responses to overload training in endurance sports. Eur J Appl Physiol 1992; 64(4): 335–44
Flynn MG, Pizza FX, Boone Jr JB, et al. Indices of training stress during competitive running and swimming seasons. Int J Sports Med 1994; 15(1): 21–6
Hooper SL, MacKinnon LT, Gordon RD, et al. Hormonal responses of elite swimmers to overtraining. Med Sci Sports Exerc 1993; 25(6): 741–7
Lehmann M, Wieland H, Gastmann U. Influence of an unaccustomed increase in training volume vs intensity on performance, hematological and blood-chemical parameters in distance runners. J Sports Med Phys Fitness 1997; 37(2): 110–6
Urhausen A, Gabriel HH, Weiler B, et al. Ergometric and psychological findings during overtraining: a long-term follow-up study in endurance athletes. Int J Sports Med 1998; 19(2): 114–20
Costill DL, Flynn MG, Kirwan JP, et al. Effects of repeated days of intensified training on muscle glycogen and swimming performance. Med Sci Sports Exerc 1988; 20: 249–54
Tanaka H, West KA, Duncan GE, et al. Changes in plasma tryptophan branched chain amino acid ratio in responses to training volume variation. Int J Sports Med 1997; 18(4): 270–5
O’Connor PJ, Morgan WP, Raglin JS. Psychobiologic effects of 3 d of increased training in female and male swimmers. Med Sci Sports Exerc 1991; 23(9): 1055–61
Morgan WP. Psychological components of effort sense. Med Sci Sports Exerc 1994; 26(9): 1071–7
Barron JL, Noakes TD, Levy W, et al. Hypothalamic dysfunction in overtrained athletes. J Clin Endocrinol Metab 1985; 60(4): 803–6
Snyder AC, Kuipers H, Cheng B, et al. Overtraining following intensified training with normal muscle glycogen. Med Sci Sports Exerc 1995; 27(7): 1063–70
O’Connor PJ, Raglin JS, Morgan WP. Psychometric correlates of perception during arm ergometry in males and females. Int J Sports Med 1996; 17(6): 462–6
Morgan WP, Costill DL, Flynn MG, et al. Mood disturbance following increased training in swimmers. Med Sci Sports Exerc 1988; 20(4): 408–14
Lehmann M, Dickhuth HH, Gendrisch G, et al. Training-overtraining: a prospective, experimental study with experienced middle- and long-distance runners. Int J Sports Med 1991; 12(5): 444–52
Hedelin R, Kentta G, Wiklund U, et al. Short-term overtraining: effects on performance, circulatory responses, and heart rate variability. Med Sci Sports Exerc 2000; 32(8): 1480–4
Lehmann M, Mann H, Gastmann U, et al. Unaccustomed high-mileage vs intensity training-related changes in performance and serum amino acid levels. Int J Sports Med 1996; 17(3): 187–92
Snyder AC, Jeukendrup AE, Hesselink MK, et al. A physiological/psychological indicator of over-reaching during intensive training. Int J Sports Med 1993; 14(1): 29–32
Smith LL. Cytokine hypothesis of overtraining: a physiological adaptation to excessive stress? Med Sci Sports Exerc 2000; 32(2): 317–31
Mackinnon LT, Hooper SL. Plasma glutamine and upper respiratory tract infection during intensified training in swimmers. Med Sci Sports Exerc 1996; 28(3): 285–90
Fry RW, Grove JR, Morton AR, et al. Psychological and immunological correlates of acute overtraining. Br J Sports Med 1994; 28(4): 241–6
Rowbottom DG, Keast D, Goodman C, et al. The haematological, biochemical and immunological profile of athletes suffering from the overtraining syndrome. Eur J Appl Physiol 1995; 70(6): 502–9
Mackinnon LT, Hooper SL, Jones S, et al. Hormonal, immunological, and hematological responses to intensified training in elite swimmers. Med Sci Sports Exerc 1997; 29(12): 1637–45
Hooper SL, Mackinnon LT, Howard A, et al. Markers for monitoring overtraining and recovery. Med Sci Sports Exerc 1995; 27(1): 106–12
Shephard RJ, Shek PN. Acute and chronic over-exertion: do depressed immune responses provide useful markers? Int J Sports Med 1998; 19(3): 159–71
Mackinnon LT. Chronic exercise training effects on immune function. Med Sci Sports Exerc 2000; 32 (7 Suppl.): S369–76
Gabriel H, Kindermann W. The acute immune response to exercise: what does it mean? Int J Sports Med 1997; 18Suppl. 1: S28–45
Gabriel HH, Urhausen A, Valet G, et al. Overtraining and immune system: a prospective longitudinal study in endurance athletes. Med Sci Sports Exerc 1998; 30(7): 1151–7
Mackinnon LT. Special feature for the Olympics: effects of exercise on the immune system: overtraining effects on immunity and performance in athletes. Immunol Cell Biol 2000; 78(5): 502–9
Mackinnon LT, Hooper S. Mucosal (secretory) immune system responses to exercise of varying intensity and during overtraining. Int J Sports Med 1994; 15Suppl. 3: S179–83
Halson SL, Lancaster GI, Jeukendrup AE, et al. Immunological responses to overreaching in cyclists. Med Sci Sports Exerc 2003; 35(5): 854–61
Pyne DB, Gleeson M. Effects of intensive exercise training on immunity in athletes. Int J Sports Med 1998; 19Suppl. 3: S183–91
Rowbottom DG, Keast D, Morton AR. The emerging role of glutamine as an indicator of exercise stress and overtraining. Sports Med 1996; 21(2): 80–97
Parry-Billings M, Budgett R, Koutedakis Y, et al. Plasma amino acid concentrations in the overtraining syndrome: possible effects on the immune system. Med Sci Sports Exerc 1992; 24(12): 1353–8
Urhausen A, Gabriel HH, Kindermann W. Impaired pituitary hormonal response to exhaustive exercise in overtrained endurance athletes. Med Sci Sports Exerc 1998; 30(3): 407–14
Vervoorn C, Quist AM, Vermulst LJ, et al. The behaviour of the plasma free testosterone/cortisol ratio during a season of elite rowing training. Int J Sports Med 1991; 12(3): 257–63
Adlercreutz H, Harkonen M, Kuoppasalmi K, et al. Effect of training on plasma anabolic and catabolic steroid hormones and their response during physical exercise. Int J Sports Med 1986; 7Suppl. 1: 27–8
Stone MH, Keith RE, Kearney JT, et al. Overtraining: a review of the signs, symptoms and possible causes. J Appl Sport Sci Res 1991; 5: 35–50
Lehmann M, Schnee W, Scheu R, et al. Decreased nocturnal catecholamine excretion: parameter for an overtraining syndrome in athletes? Int J Sports Med 1992; 13(3): 236–42
Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. Heart rate variability: standards of measurement, physiological interpretation, and clinical use. Eur Heart J 1996; 17(3): 354–81
Uusitalo AL, Uusitalo AJ, Rusko HK. Exhaustive endurance training for 6–9 weeks did not induce changes in intrinsic heart rate and cardiac autonomic modulation in female athletes. Int J Sports Med 1998; 19(8): 532–40
Uusitalo AL, Uusitalo AJ, Rusko HK. Heart rate and blood pressure variability during heavy training and overtraining in the female athlete. Int J Sports Med 2000; 21(1): 45–53
Smith DJ, Norris SR. Changes in glutamine and glutamate concentrations for tracking training tolerance. Med Sci Sports Exerc 2000; 32(3): 684–9
Hedelin R, Wiklund U, Bjerle P, et al. Cardiac autonomic imbalance in an overtrained athlete. Med Sci Sports Exerc 2000; 32(9): 1531–3
Acknowledgements
No sources of funding were used to assist in the preparation of this review. The authors have no conflicts of interest that are directly relevant to the content of this review.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Halson, S.L., Jeukendrup, A.E. Does Overtraining Exist?. Sports Med 34, 967–981 (2004). https://doi.org/10.2165/00007256-200434140-00003
Published:
Issue Date:
DOI: https://doi.org/10.2165/00007256-200434140-00003