By Elissa Rosen, MD, CEDS-S
Many athletes from recreational to professional go through periods of higher training volumes in order to enhance performance. (1) These high intensity periods should then be followed by periods of lower intensity and lower volume of training. This practice of high intensity cycles followed by lower intensity cycles is called periodization.(1) Periodization is one way to optimize performance while reducing risk of overtraining. Athletes that maintain high training volumes year-round and/or do not incorporate adequate rest and recovery into their training cycles are at risk for overtraining syndrome (OTS). Recovery is an essential part of any training program. Recovery involves not only physical recovery such as days off from training, but also good hydration, nutrition, sleep, and mental recovery. Today, we are going to do a general overview of OTS including terminology, symptoms, diagnosis, treatment, and prevention. Keep in mind that OTS can happen to any active person not just high level or elite athletes!
Terminology
Overtraining is believed to cause a range of responses that exist along a continuum with time to recovery being a major variable that distinguishes them. (2) There are several terms that are used to describe states of overtraining along this continuum. Functional overreaching (FOR) is defined as a short-term (no more than 2 weeks) decline in athletic performance due to increased training. After a period of rest, performance improves. (2) In non-functional overreaching (NFOR) intense training leads to a longer performance decrement (weeks to months), but full performance recovery occurs after sufficient rest. Unlike with FOR, NFOR may be accompanied by psychologic and physiologic symptoms. (1) OTS is defined as a prolonged decline in sports performance (usually greater than 2 months) with many associated psychologic and physiologic symptoms that will be described in more detail below. Recovery from OTS can take many, many months and can be career-ending for some athletes. (2) A common occurrence in those with NFOR/OTS is that as performance declines training is ramped up in response thinking that undertraining is the problem which, of course, just exacerbates the real issue.
Incidence and Pathophysiology
Studies on OTS are limited due to variations in diagnostic criteria and small sample sizes; therefore, data on incidence and prevalence is lacking. OTS is most commonly seen in endurance sports such as swimming, cycling, and running. (3) For elite and non-elite endurance athletes the lifetime prevalence of NFOR/OTS is estimated at about 60% and 30% respectively. (3) Data also suggests that those who do develop OTS are more likely to relapse and develop it again in the future.
While a lot of theories exist as to what causes OTS, there is no conclusive data on the pathophysiology of this syndrome. The current theories range from autonomic imbalance to glycogen depletion to central fatigue to cytokines and sleep disturbances to name a few. (1) What triggers these biochemical and hormonal changes is more complex than just heavy training without adequate rest. Other factors that have been identified as potential triggers of OTS include an excessive number of competitions, altitude exposure, sleep disturbances, occupational and personal stressors, previous illness, monotony of training, and prior heat injury. (2)
Diagnosis and Symptoms
There are no reliable markers (blood or otherwise) for the diagnosis of OTS at this time. (1) In addition, there are no widely accepted guidelines in the health and sports community for making a diagnosis of OTS. Presently, a diagnosis is made by collecting a thorough clinical history that demonstrates decreased athletic performance in spite of months of recovery, disturbances in mood, and the absence of other possible causes of performance decline. A few examples of other conditions that when left untreated can impact performance include thyroid abnormalities, anemia, malnutrition such as from eating disorders or RED-S, iron deficiency, undiagnosed asthma, infections, cardiovascular disease, and certain mental health disorders. (2)
Common mood symptoms in those with OTS can include lack of motivation, depression, irritability, restlessness, or difficulty concentrating. These symptoms often present first. In addition to poor athletic performance, physical symptoms of OTS include fatigue, persistent muscle soreness or stiffness, increased daytime sleepiness, loss of appetite, frequent illness (such as upper respiratory tract infections), or persistent overuse injuries. (1, 2) Physical examination is often normal though at times blood pressure and heart rate may be high.
When considering a diagnosis of OTS, blood work can be ordered that is tailored to the individual’s symptoms in order to rule out other medical causes of their symptoms. (3) Again, no markers including biochemical, hematologic, hormonal, or immunologic have been clearly identified in OTS though there are certainly some markers that can be suggestive of it and can be ordered and interpreted by providers with more expertise in OTS.
Treatment and Prevention
The treatment of OTS is rest. Since many variables, as previously described, play into OTS, it is also important to take a whole person approach to treatment. This includes addressing any emotional stressors or mental health concerns as well as getting good sleep and nutrition. The idea of resting in and of itself can be hard for some highly active individuals so having good psychological support by means of a therapist can be helpful. A sports dietitian may also be helpful in those who may have struggled with fueling adequately for their sport.
Prevention of OTS should be a key focus of athletes, coaches, or anyone who works with athletes, such as athletic trainers. Education about and screening for OTS in athletes are also an important parts of prevention. Some important keys to prevention of OTS that have been identified thus far include: periodization of training, ensuring adequate calories and carbohydrate ingestion for training load, ensuring adequate hydration and sleep, adjusting training volume based on performance and mood, being aware of and addressing emotional stress (personal, job, etc.), refraining from training during periods of infection or high stress, and tapering for competition. (2)
The Gaudiani Clinic physicians enjoy supporting athletes by addressing their training and fueling concerns and work in conjunction with a treatment team to ensure the whole person receives expert and compassionate care.
References
1. Halson S. Overtraining Syndrome in Athletes. UpToDate. 2020.
2. Kreher JB and JB Schwartz. Overtraining Syndrome: A practical guide. Sports Health. 2012.
3. Cardoos N. Overtraining syndrome. Curr Sports Med Rep. 2015 May-Jun; 14 (3): 157-8
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