The goal of training competitive athletes is to provide a training load that enhances performance. Along the way, athletes go through different phases, from “undertraining” or aggressive rest and taper between seasons to “Over” (OR) and “Overtraining” (OT), including maladaptation and decreased competitive performance.  When overtraining is co-occurring with other stressors and recovery time is insufficient, performance loss leads to chronic maladaptation This can lead to “Overtraining Syndrome” (OTS), also known as Paradoxical Disorder Syndrome (PDS). 
In exercise physiology, overtraining syndrome is observed as the result of a training program that is unbalanced in the levels of exercise stress load, non-training (life) stress load, and rest periods. Athletes progress from a state of adequate training to overtraining (OR) and ultimately Overtraining (OT) state if no tuning is performed. Preventive management and early recognition are necessary to ensure that the condition does not progress to a potentially severe and end-of-sports stage.
It is most commonly seen in endurance events such as swimming, cycling, or running. Prevalence and incidence data for true OTS are lacking ; among elite collegiate endurance athletes, the prevalence of affected individuals was once close to 10% (range 7-21%). Prevalence of Overtraining Syndrome Nearly 60% of elite runners, and even among non-elite runners nearly a third experience OTS at some point in their running career.  High-level athletes have an incidence of approximately 30-40% in all sports except running. 
Types of Overtraining Syndrome
Two types of OTS have been proposed:
- Hypoarousal is also known as Parasympathetic or Addison’s OTS. It is commonly seen in endurance athletes (distance runners, rowers, cross-country skiers, cyclists, and swimmers).
- Hyperarousal is also known as sympathetic or Basedou’s OTS. It is common in strength athletes (sprinters and lifters) and occurs less frequently than the low arousal form. 
Difference Between Overtraining and Overtraining
- Overtraining (OR) is a short-term decline in performance capacity due to the accumulation of training and/or non-training stress, with or without associated physical and psychological signs of maladaptation (see Table 1 below), during which time, expressed Recovery may need to depend on days to weeks.  Overreaching (OR) is practiced by elite level athletes and their coaches to improve athletic performance. These intensive training periods may result in a temporary decrease in performance; however, when an appropriate recovery period is reached, super Compensation (the body’s positive adaptive response to physical stress) occurs and the athlete’s performance improves substantially compared to baseline.
- Overtraining (OT) is a long-term decline in performance ability due to increased training and/or non-training stress, with or without associated physical and psychological signs of maladaptation, where performance recovery may take weeks or weeks months. So OTS is the result of OT.  The syndrome is a continuum from training fatigue to overload and eventually to complete overtraining syndrome.
This short-term efficient form of overtaking (OR) is called functional OR (FOR). However, if FOR persists for too long (i.e., weeks) , it becomes non-functional or (NFOR), which becomes OT and the athlete moves towards OTS.  These events and developments can be accessed via Malnutrition diseases and sleep disorders. The difference between these two training conditions is therefore the length of time required to return to performance rather than the duration or type of training stress or degree of physiological impairment.
Parasympathetic low arousal Sympathetic hyperarousal Decreased physical function Easily tired or lethargic Easily fatigued Depression Hyperactive Normal or sleep disturbance Sleep disturbance Normal constant weight or weight loss Weight loss Low resting heart rate Increased resting state HR and BP hypoglycemia during exercise Slow recovery of HR and BP after exercise Loss of desire to compete Female amenorrhea Female amenorrhea Male hypogonadism Male hypogonadism Increased incidence of infection Increased incidence of infection Maximal lactate reduction Response to exercise reduces maximal lactate in response to exercise
Table 1: Pathophysiological features of the hypoarousal and hyperarousal forms of the overtraining syndrome 
Stages of Overtraining Syndrome
Stages of OTS
Overtraining syndrome can occur in three distinct stages:
- Phase 1: Also known as functional overtraining. Very subtle signs and symptoms indicate the early stages of an athlete starting to overtrain.
- Stage 2: Also known as sympathetic overtraining. A more pronounced stage is associated with specific neurohormonal and mechanical imbalances, resulting in distinct signs and symptoms.
- Stage 3: Also known as parasympathetic overtraining. The severe end of overtraining is associated with exhaustion of neurological and hormonal factors.
There are many theories, but the cytokine and autonomic dysfunction hypothesis is the most accepted and comprehensive in terms of established symptoms and pathology. These two theories overlap because dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis inevitably leads to chronic inflammation.
Theories of OTS
OTS and its implications
- Glycogen Hypothesis – Depletion of glycogen stores is associated with fatigue and poor performance. Likely a contributing factor, associated with several genotypes and malnutrition, but does not explain most of the associated conditions. 
- Glutamine Hypothesis – Glutamine is essential for immune cell function DNA/RNA synthesis nitrogen transport gluconeogenesis and acid-base homeostasis. Prolonged or repeated high-intensity exercise is associated with decreases in plasma glutamine. Current evidence is inconclusive Only weak relationships to OTS are shown. However, glutamine supplementation may have a role.
- Oxidative Stress Hypothesis – Exercise produces reactive oxygen species that cause muscle fatigue, soreness and inflammation. Higher levels were detected in overworked athletes. It’s unclear if this is a trigger or the result of overtraining syndrome. 
- Cytokine Hypothesis – Repetitive microtrauma induced by vigorous exercise leads to release of pro-inflammatory cytokines. Inadequate recovery and failure to resolve the inflammatory cascade can lead to chronic systemic inflammatory responses, including IL-1-α and TNF-α. This is an attractive hypothesis because it explains several features of OTS, including decreased glycogen, decreased glutamine, decreased tryptophan/serotonin, decreased appetite, sleep disturbance, and depression. It also accounts for altered immunity. 
- The Autonomic Nervous System and the HPA Hypothesis – Imbalances between the sympathetic/parasympathetic nervous system and changes in HPA axis activity and feedback lead to many effects consistent with the exhaustion phase of Hans Selye’s theory of adaptation.  Disharmony HPA feedback results in persistent cortisol secretion and cortisol resistance (similar to insulin resistance), resulting in widespread neurochemical hormonal and immune abnormalities.  
- Early single-sport specialization
- Significantly increased training load in a short period of time
- Training preparation for important events
- Undue pressure from parents and/or coaches to succeed
- In addition, the risk of OTS was positively correlated with skill level and previous incidence of overtraining syndrome. 
One of the most important challenges of overtraining syndrome is early identification. Once established treatment becomes more difficult and long term. Diagnosis relies on evaluation of all aspects.
Look for potential triggers when viewing history:
- Increased training load without adequate rest
- Training monotony
- Multiple competitions
- Sleep abnormalities
- Additional stressors – personal work, etc.
- Recent illness or injuries
- Environmental exposure – high altitude, high temperature and cold 
Rule Out Organic Disease
- Some organic diseases may present in a similar manner to overtraining syndrome and are often overlooked because the population tends to be younger and the disease is less common. 
- Undiagnosed lung disease (asthma)
- Hormonal disorders (thyroid diabetes)
- Infections (Hepatitis HIV Myocarditis Lyme EBV)
- Malnutrition/Eating Disorders (RED-S or Relative Energy Deficiency in Exercise) is a state of low energy due to nutritional deficiencies relative to the level of training. Originally identified as the female athlete triad (anorexia amenorrhea osteoporosis), it is now known to affect both males and females Women are equal. Although similar in presentation, it can be distinguished from overtraining syndrome. RED-S is primarily a low-energy state rather than a low-performance state; food anxiety and body image concerns are more intense; bone damage (stress fractures) rather than muscle damage occurs; RED-S can be quickly reversed with proper nutrition. 
Signs and Symptoms
Symptoms vary from person to person and may occur in any order. However, even one or two may indicate early OTS and should not be ignored. The more symptoms, the more severe the condition.
- Inability to complete a training session
- Tired but unable to sleep
- Loss of “finishing kick”
- Increased irritability
- Depressed mood/Enhanced PMS
- Weight loss/Weight Gain
- Persistent thirst
- Recurrent colds
- These findings vary from person to person. A high resting heart rate (10-30 bpm above the normal range) is most reliable and usually occurs in the early stages of OTS:
- Increased resting heart rate
- Increased fatigued/Sickly appearance
- Muscle tenderness/tightness
- vague muscle and/or joint pain
- Weak hair/nails
Various measurement tools have been developed to properly monitor training load and quantify recovery rates. An important feature of these measurement tools is that they should be easy to administer, non-invasive and sensitive to change.
Ratings on the Perceived Exercise Scale are important determinants of impending fatigue during exercise testing and are generally recognized as a useful tool for prescribing aerobic exercise intensity. A study introduced the concept of the Perceived Exercise Scale (sRPE) in which an athlete Subjectively estimate the overall complexity of the entire exercise after completion.  Ideally, the total weekly RPE must be varied to ensure different intensities. Additionally, monitoring RPE for specific workouts can track performance and fatigue. If a routine is in Early in the season, but becomes 8 midway through, when an athlete may show signs of Paradoxical Disorder Syndrome (PDS).
Measurement of recovery heart rate is also recommended as a valuable tool. One study showed that the selected submaximal test exercise intensity must elicit a heart rate between 85% and 90% of HRmax, since the lowest daily variation is found at this intensity.  From testing to Testing for heart rate recovery changes of >6 bpm or submaximal heart rate changes of >3 bpm can be flagged as significant changes under controlled conditions. These changes may be due to improvement/decrease in training status or accumulation of fatigue from functional training Out of bounds (FOR).
- Physical and psychological testing appear to be the most reliable and useful methods of assessing impending or established OTS. These tests include time-to-fatigue tests, sport-specific maximal aerobic function tests, and sport-specific strength or power tests. 
- A study suggests that using two maximal incremental exercise tests 4 hours apart can be a useful tool for assessing the decline in performance commonly observed in OTS athletes. A reduction in exercise time of at least 10% was considered significant. Furthermore, this reduction Performance needs to be verified by specific changes in hormone concentrations. 
- The Mood State Questionnaire (or POMS) is a simple and easy test with good reliability in confirming the diagnosis of OTS. By assigning values to self-perceived issues, including components such as fatigue, energy, tension, anger, confusion, depression, and overall emotional state ratings, it is possible to Logging and monitoring. 
- Other tests include the Multicomponent Training Stress Scale (MTDS) and the Recovery Athlete Stress Questionnaire (REST-Q) assessment, among others. They integrate mental and physical self-assessments of stress and recovery. The REST-Q questionnaire is more accessible and generally usable version as well as athlete-specific versions.
- Psychomotor speed tests are becoming more and more beneficial. They are simple non-invasive and readily available. They appear to have high validity in assessing athletic performance combining mental and motor skills. Examples include Zig-zag tracking Gibson spiral maze and STROOP Test.
Blood tests that have been used to diagnose OTS include blood sugar levels (often elevated due to mild insulin resistance in a few people), lactate, glutamine cortisol, but are invasive, difficult to interpret and often unreliable. Each hormone has a predefined exercise-induced pattern. When studying hormonal markers of training adaptation, it is very important to focus on the informative potential of specific hormones and to sample them synchronously according to their response patterns.  However, testing central hypothalamic/pituitary regulation requires Functional tests are considered invasive and require diagnostic expertise, and these tests are time-consuming and expensive. Although there is not a single biomarker for OTS, there are some promising biomarkers in the field of investigation and research. due to excessive oxidative stress Sports Many studies have studied the redox state of athletes. Biomarkers of oxidative stress, such as decreased oxidized glutathione ratios and urinary isoprostanes, are expected to scale training load and overload status. 
Once an athlete shows signs of OTS, treatment needs to be initiated quickly and thoroughly to be effective. Ignoring the signs or not taking action will lead to further deterioration and take longer to recover.
Stage 1 OTS does not require any treatment other than adjustments to overload training during appropriate recovery periods.  This usually improves symptoms and even training within one to four weeks. This rapid progress will be demonstrated in a test of maximal aerobic function (MAF)  or other assessments, including harm reduction and mental status. The MAF test involves measuring an athlete’s workout while maintaining a submaximal heart rate. (Submaximal heart rate corresponds to low to moderate intensity training using the MAF 180 formula. This makes Athletes find their ideal maximum aerobic heart rate and use it as the basis for all aerobic training. When overdone, this figure shows a rapid transition to anaerobic work.  A typical problem with overtraining during the first phase is an imbalance between aerobic and anaerobic capacity. Although it can be determined With several tests, it is not difficult to compare maximal aerobic function with maximal anaerobic function. Aerobic capacity can be determined by MAF testing, while anaerobic function can be determined by competition performance. For example, if you can perform a MAF test at 7 o’clock, the imbalance is very obvious 5 minutes per mile, but 5 or 10K races under 5 minutes per mile. It is not uncommon for skilled athletes in Phase 1 (or the beginning of Phase 2) to compete at a high level but have poor aerobic function. (The decrease in performance level is not noticeable until the middle and late stages of overtraining syndrome).
The treatment of nonfunctional hyperextension (NFO) and OTS is relative rest.  suggested increasing the intensity starting with 5-10 minutes per day until 1 hour can be tolerated.  It is not clear which strategy is best and therefore whether the motivation to exercise is internal or external This should be taken into account when recommending complete versus relative rest. Allowing for cross-training might overcome some of the inevitable frustration of a suspended season. Restorative sleep is one of the most important factors in healing as well as improving nutrition and hydration. this is Athletes are often difficult to accept, so involving a sports psychologist can be helpful.
The reduction in activity and training needs to be quite profound, which surprises most athletes. However, failure to follow proper rest and recovery protocols will result in a high likelihood of relapse. The recommended time frame varies by OTS phase, as shown in Table 2 below. However, during Phase 1, participation in competitions does not have to stop and the frequency of competitions should definitely be kept to a minimum. 
Phase 1 Phase 2 Phase 3 Reduce training by 50-70% Yes Yes Yes Eliminate high intensity Yes Yes Stop competition No Yes Recovery time 1-4 weeks 4-12 weeks 12-52 weeks
Table 2: Treatment options for each stage of OTS.
The main components of OTS prevention are regular screening and education. Athletes should be educated about the risks of overtraining, which are the first signs of overtraining and can be identified by increased levels of perceived exertion for a given workload. no evidence to support Means of protection against PDS/OTS. However, observation of training load performance indicators and mood questionnaires may help interrupt progression from functional overtraining (FO) to nonfunctional overtraining (NFO) and ultimately to OTS.  Studies have shown that the reduction When the training load was adjusted according to the emotional state questionnaire, the swimmers’ “burnout” dropped from 10% to zero. They found that when the emotional state was lowered, so was the training load. 
The main components of prevention are screening and education. One should educate athletes who are at risk of overtraining that one of the first signs of overtraining is an increase in perceived exertion ratings for a given workload.
The most common ways to monitor training and prevent overtraining syndrome are:
- Retrospective Questionnaires
- Training Diary: It can be used not only to detect subtle differences in training load, but also to detect subjective parameters such as muscle soreness, physical and mental health, etc. Modify training volume and intensity based on performance and mood. Make sure you’re getting enough carbohydrates while exercising And maintain >6 hours of rest between bouts of exercise.
- Physiological screening
- The direct observational method
- The MAF test is perhaps the most powerful and useful tool for assessing overtraining at its earliest stages, giving the first objective signs even before symptoms appear. This test should be done every four weeks to detect OTS early.
- Early recognition and treatment of adrenal dysfunction is important to prevent overtraining (easy to do with regular saliva testing).
- Psychological screening  and perceived exertion ratings  of athletes have recently gained increasing acceptance.
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