Overtraining syndrome

{Overtraining syndrome or OTS occurs in athletes when amount or intensity of training exceeds the body's ability to recover. It is common in nearly every sport, with typical symptom patterns differing according to whether the sport is mainly aerobic or mainly anerobic in nature. OTS can also occur in children and adolescents.

Overreaching
Overreacting is a normal part of athletes' training, causing a temporary decline in performance followed by a reduction in training, which should then lead to adaption and improved performance.

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.

"OTS remains a clinical diagnosis with arbitrary definitions per the European College of Sports Science’s position statement. History and, in most situations, limited serologies are helpful. However, much remains to be learned given that most past research has been on athletes with overreaching rather than OTS."

Nonfunctional overreaching
Nonfunctional overreaching or NFO is similar to overtraining syndrome, but less severe and quicker to recover from.

Terms
The terms overtraining syndrome, burnout and chronic fatigue syndrome are often incorrectly used.

Causes
The causes of overtraining syndrome are not clearly established, and may involve a combination of factors.

Overtraining is the "breaking-down rather than building-up; usually as a result of improper rest intervals between exercise sessions."

Diagnosis
There is no diagnostic biomarker or test for overtraining syndrome. Diagnosis consists of history, symptom profile, and excluding other causes for the symptoms.

Overtraining syndrome vs ME/CFS
Overtraining syndrome is marked with prolonged fatigue which can result in it investigations for chronic fatigue syndrome (CFS), or other fatiguing illnesses, as there are no laboratory tests to confirm OTS. However, chronic fatigue syndrome is a distinct neurological disease with symptoms affecting many bodily systems, and should not be confused with idiopathic chronic fatigue, which is long-lasting fatigue with no known cause.

Chronic fatigue syndrome erroneously diagnosed
A large number of different sets of diagnostic criteria exist for myalgic encephalomyelitis and chronic fatigue syndrome, which can cause confusion in excluding many other conditions that are potential causes of chronic fatigue and other symptoms. Some clinicians also use the terms chronic fatigue syndrome to incorrectly refer to idiopathic chronic fatigue, which is not a neurological disease but a term for any long-term unexplained fatigue.

Medical tests are needed to diagnose ME/CFS - while no particular test can diagnose it, tests are needed to investigate other possible causes of the symptoms. A large UK study of 377 patients referred to a specialist ME/CFS treatment found many patients were wrongly diagnosed:

Media reports of athletes and CFS
There have been unverified media reports of athletes diagnosed with myalgic encephalomyelitis (ME) or CFS who have recovered in a relatively short period of time after rest, supplementation, and diet changes. However, scientific studies and case reports on this are lacking. Dietary changes and rest have not been found to be a cure for ME/CFS, and no dietary changes or supplements have been found to be an effective treatment in clinical trials. In ME/CFS, a healthy balanced diet is suggested and nutritional tests should be run prior to diagnosis to identify any alternative causes of fatigue or impairment.

Physiological

 * Altered resting heart rate - either bradycardia or raised heart rate at rest
 * Fatigue
 * Decreased physical performance
 * Decreased lactate response
 * Decreased maximum work capacity
 * Frequent gastrointestinal upsets
 * Headaches
 * Hormone imbalance includes elevations of cortisol with secondary lowering of testosterone and DHEA levels
 * A decrease in muscular strength
 * Early waking and sleep problems
 * Lack of appetite
 * Lower percent of body fat than pre-illness levels
 * Amenorrhea is common in women and teenager girls
 * Muscle soreness and tenderness, or tight muscles

Psychological

 * Decreased motivation to train
 * Difficulty concentrating during work, school, or training
 * Mood changes, especially feelings of sadness and depression or clinical depression

Differences from CFS
Overtraining syndrome includes a much narrower group of symptoms, can only be caused by repeatedly overexercising, and unlike CFS, is not either neurological in nature or a common cause of significant and long term disability affecting all aspects of life.

ME/CFS symptoms not present in overtraining syndrome

 * post-exertional malaise, which is not limited to exercise, is the hallmark symptom of ME/CFS, and may be delayed by up to 3 days
 * chronic pain, which is pain lasting for over six months, is common in ME/CFS, and may include joint pain or nerve pain rather than just muscle pain
 * the minimum level of impairment for diagnosis is typically only being able to function at 50% of their previous level in everyday day, although this depends on the diagnostic criteria used
 * some patients are housebound or bedbound, and the 25% of ME/CFS patients with severe and very severe ME are wheelchair users or bedbound
 * typically functioning is lower than that patients multiple sclerosis and class 3 heart failure
 * co-morbidities frequently occur, including POTS, IBS, fibromyalgia, Hashimoto's thyroiditis, and migraines
 * digestive symptoms, which are persistent and may include nausea or vomiting, even at rest, new onset irritable bowel syndrome or gluten sensitivity; in particularly severe cases some patients require a feeding tube
 * endocrine symptoms may include thyroid problems, inability to regulate body temperature, and unexplained weight loss or gain
 * sensory overload  symptoms, including photophobia, hyperacusis, touch sensitivity and even allodynia are fairly common in ME/CFS
 * exercise or over-exertion causes noticeable cognitive dysfunction
 * concentration is significantly impaired, and too much mental activity causes post-exertional malaise and an increase in symptoms such as pain, muscle weakness, dizziness and gastrointestinal symptoms; some patients with ME/CFS are unable to watch TV due to severe cognitive dysfunction
 * Very severe ME/CFS can be life-threatening and a number of people have died
 * Prognosis is very poor, most people do not fully recover from ME/CFS; in overtraining syndrome most recover within weeks or months
 * ME/CFS can occur in sedentary people
 * ME/CFS is a female predominant disease
 * ME/CFS is most commonly caused by a virus or bacterial disease, although severe injury and other events are also common
 * overtraining, inadequate food intake and poor nutrition are not among the many pre-onset triggers or risk factors commonly reported; nutritional deficiencies must be ruled out as a possible cause before diagnosis
 * significant brain and spinal cord changes have been found in patients with ME/CFS, including in autopsies of patients who have died from the illness
 * paralysis is reported in some patients
 * symptoms may not be diagnosed unless present for at least 6 months, in the most commonly used diagnostic criteria  (Full text)

Overtraining signs symptoms not present in ME/CFS

 * mood changes - these are not a diagnostic symptom of ME/CFS, and not any more common than in ME/CFS compared to other chronic illnesses. In overtraining syndrome, mood changes are a key indicator.

Syndrome recognition
Overtraining syndrome remains poorly defined. In 2012, the European College of Sport Science (ECSS) and the American College of Sports Medicine published a joint statement to help clarify OTS.


 * Overtraining: Undermining Success?

Notable studies and articles

 * 1998, The case history of an elite ultra-endurance cyclist who developed chronic fatigue syndrome (Abstract)
 * 1998, Overtraining in sport. (Abstract)


 * 2000, The Differential Diagnosis and Clinical Approach to the Athlete With Chronic Fatigue


 * 2004, Does overtraining exist? An analysis of overreaching and overtraining research. (Abstract)

"This is the first evidence of a T cell defect in fatigued athletes, and of its reversal following Probiotic therapy."
 * 2005, Reversal in fatigued athletes of a defect in interferon γ secretion after administration of Lactobacillus acidophilus (Full Text)


 * 2012, Overtraining Syndrome - A Practical Guide (Full Text)


 * 2012, Prevention, diagnosis and treatment of the overtraining syndrome: Joint consensus statement of the European College of Sport Science (ECSS) and the American College of Sports Medicine (ACSM) (Full text)

Learn more
"The United States National Institutes of Health (NIH) has issued a draft report that highlights the dire need for scientific research that will help find a cure for the millions of people suffering from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) worldwide. The report also highlights the fact that the decades-old UK Oxford criteria for ME/CFS are severely “flawed,” and that continuing to use these criteria may “cause harm.” Further, the NIH report says that the Royal Society definition should “be retired” and replaced with a single case definition agreed to by the ME/CFS community."
 * Joint College's Statement (2012)
 * The Differential Diagnosis and Clinical Approach to the Athlete With Chronic Fatigue
 * US NIH Report Calls for UK Definition of ME/CFS to be Scrapped (Oxford criteria)