"I overtrained" is a phrase heard in the gym every week. However, true overtraining syndrome is a rare and severe condition that athletes sometimes take months to recover from. The editors explain how to distinguish normal fatigue from an alarm signal, what signs should be monitored and how to build training to avoid this.
From fatigue to syndrome: terminology
Training in its essence is a controlled disturbance of the body's balance. After a load, working capacity temporarily decreases, and during rest it is restored with a "reserve". This supercompensation mechanism is at the heart of progress. Problems begin when the balance between load and recovery is systematically disturbed.
A joint consensus statement of the European College of Sports Science and the American College of Sports Medicine (Meeusen et al., 2013) distinguishes several states on this continuum. Functional overreaching is a short-term planned decrease in results after an intensive block followed by progress. Dysfunctional overexertion is a condition when results drop in weeks, psychological and hormonal symptoms appear, and supercompensation does not occur.
Overtraining syndrome (OTS) is the extreme point of this scale. It is characterized by a prolonged, more than several months, decline in working capacity, which is not explained by other diseases. The difference between non-functional overstress and OTS can often only be established in retrospect—by how long recovery took.
For most amateurs who train a few times a week, true OTS is unlikely. They are much more likely to experience accumulated fatigue due to a combination of training, lack of sleep, stress at work, and a calorie deficit.
| State | Duration of reduced performance | Consequence |
|---|---|---|
| Acute fatigue | Hours - days | Normal part of the training process |
| Functional overreaching | Days - up to 2 weeks | Improvement after a deload |
| Non-functional overreaching | Weeks - months | Lack of progress, symptoms |
| Overtraining syndrome | Months and longer | Prolonged loss of fitness; possible end of the season |
Why overtraining occurs
The most obvious reason is overload: sudden increases in volume or intensity, monotonous programs without wave-like planning, lack of unloading weeks. However, the ECSS/ACSM consensus emphasizes that training load is rarely the only factor.
Lack of sleep, psychological pressure, work, study, travel and changing time zones are added to the "general stress budget" of the body. Energy deficit plays a big role. The RED-S (Relative Energy Deficit in Sport) concept described in the IOC Consensus (Mountjoy et al., 2018) shows how chronic energy deprivation disrupts hormonal regulation, immunity and bone health—and can clinically be very similar to overtraining.
Several hypotheses of mechanisms have been proposed: glycogen depletion, imbalance of the autonomic nervous system, hypothalamic-pituitary regulation, chronic systemic inflammation due to cytokines. None of them explain all cases, so today OTS is considered a multifactorial condition (Kreher, Schwartz, 2012).
It is also important to remember about infections. Frequent colds, viral infections with a return to training "on your feet" is a classic scenario that turns ordinary fatigue into a protracted decline.
Signs and symptoms
The main and mandatory criterion is a decrease in sports performance that does not improve after several days or weeks of rest. All the rest are accompanying signs, and their set is individual. The editors selected the most frequent of them according to the reviews.
- persistent feeling of fatigue, "heavy legs", inability to perform usual work;
- sleep disturbance — difficulty falling asleep or waking up in the middle of the night, despite fatigue;
- mood changes: irritability, apathy, loss of motivation, anxiety;
- decreased appetite and unplanned loss of body weight;
- frequent infections of the upper respiratory tract;
- changes in resting heart rate and heart rate variability (HRV);
- prolonged muscle pain and increased susceptibility to injuries;
- in women - a violation of the menstrual cycle, which always requires the attention of a doctor.
It is interesting that the "sympathetic" and "parasympathetic" variants are distinguished. The first is more often described in speed-power types: increased heart rate at rest, excitement, insomnia. The second is in terms of endurance: reduced heart rate, depression, lethargy. However, this classification is simplified and in practice mixed pictures often occur.
No single symptom alone is diagnostic. Fatigue and low mood can be a sign of anemia, hypothyroidism, depression, or infection. Therefore, the diagnosis of OTS is a diagnosis of exclusion.
Diagnostics and monitoring
There is no single laboratory marker of overtraining. The ratio of testosterone to cortisol, the level of creatine kinase, urea, immunological indicators have been studied for decades, but they are too variable and react to any load (Halson, Jeukendrup, 2004). Blood tests are useful primarily to rule out other causes: anemia, iron deficiency, thyroid gland dysfunction.
Daily tracking of simple indicators is more practical. The method of subjective assessment of load (session-RPE), proposed by Carl Foster, involves multiplying the assessment of the difficulty of training on a scale by its duration. This is how you get the weekly workload, its monotony and "tension" (Foster, 1998).
Heart rate variability has become a popular tool. Regular morning measurements allow you to see trends: a prolonged decrease in HRV relative to the individual norm may signal incomplete recovery (Plews et al., 2013). It is important to look at the moving average, not individual values.
Well-being questionnaires, sleep, mood and appetite diary are simple but well-validated tools. In sports teams, they are combined with objective data to make decisions about load correction.
Prevention and recovery
The best prevention is smart planning. Periodization with alternating heavy, medium and light weeks, planned unloading and gradual increase in volume reduces the risk of both overtraining and injuries. Tim Gabbett in his review showed that it is not the high loads themselves that are dangerous, but sharp jumps relative to what the athlete is already adapted to (Gabbett, 2016).
The second support is the basic factors of recovery: sufficient sleep, adequate energy value of the diet, a sufficient amount of carbohydrates in types for endurance and protein in strength. Trying to "dry out" and set records in the gym at the same time is a typical scenario of dysfunctional overexertion.
Extra-training stress should also be taken into account. During the session, work avrals or family problems, it is wise to temporarily reduce the volume, and not try to "squeeze" the plan at any cost.
If symptoms have already appeared, the first step is rest and examination by a sports doctor to rule out other diseases. With true OTS, recovery can take months; the return to training is gradual, with low intensity and under the control of well-being. Stimulants, "fat burners" and hormonal drugs do not help in such a situation, but only mask the problem and add risks.
Editorial conclusions
Overtraining is a continuum from normal fatigue through functional and non-functional overexertion to a rare but severe syndrome. The key criterion is a drop in results that persists after rest.
The reasons are always complex: workload, sleep, nutrition, psychological stress, infections. There is no specific analysis, so daily monitoring and exclusion of other diseases are important.
Prevention is simple, although it requires discipline: periodization, gradual increase in workload, sufficient sleep and energy, attention to body signals.
On this topic, we advise you to also read our articles "Sleep as a recovery factor", "Cardio and strength training: how to combine" and material on iron deficiency in athletes.
List of used literature
- 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. Med Sci Sports Exerc. 2013;45(1):186â205.
- Kreher JB, Schwartz JB. Overtraining syndrome: a practical guide. Sports Health. 2012;4(2):128â138.
- Halson SL, Jeukendrup AE. Does overtraining exist? An analysis of overreaching and overtraining research. Sports Med. 2004;34(14):967â981.
- Mountjoy M, Sundgot-Borgen JK, Burke LM, et al. IOC consensus statement on relative energy deficiency in sport (RED-S): 2018 update. Br J Sports Med. 2018;52(11):687â697.
- Foster C. Monitoring training in athletes with reference to overtraining syndrome. Med Sci Sports Exerc. 1998;30(7):1164â1168.
- Gabbett TJ. The training-injury prevention paradox: should athletes be training smarter and harder? Br J Sports Med. 2016;50(5):273â280.
- Plews DJ, Laursen PB, Stanley J, et al. Training adaptation and heart rate variability in elite endurance athletes: opening the door to effective monitoring. Sports Med. 2013;43(9):773â781.
