Chronic fatigue is much easier to prevent than to spend months recovering from afterwards. The editorial team has gathered practical approaches to prevention, methods of self-monitoring that really work, a standard list of examinations and the warning symptoms for which a visit to the doctor must not be put off.
Why you should not "wait for fatigue to pass"
In the sporting environment, a culture of endurance is still widespread: fatigue is perceived as a sign of diligence, and rest as weakness. Yet prolonged exhaustion worsens training quality, increases the risk of injury, lowers immune defence and may be a manifestation of an illness that requires treatment.
The longer the state lasts, the longer it takes to recover from. The consensus of the European College of Sport Science and the American College of Sports Medicine describes a continuum: functional overreaching passes within days, non-functional overreaching within weeks or months, and overtraining syndrome can last for months (Meeusen et al., 2013). A timely response allows one to stop at the first stage.
In addition, behind "sports" fatigue there may be hidden anaemia, hypothyroidism, diabetes, the aftermath of infections, depression or heart-rhythm disturbances. These conditions will not pass with rest, and their late detection makes treatment more difficult.
That is why the editorial team suggests a simple rule: if fatigue does not decrease after one or two weeks of reduced load, it is time for an examination, not for a new supplement or stimulant.
Prevention: planning, sleep, nutrition
The basis of prevention is sensible planning. Load should be increased gradually, hard and easy days alternated, and every few weeks an unloading week provided for. Special caution is needed during periods after breaks and illnesses, when the temptation to "catch up" on what was missed is strongest.
The second pillar is sleep. Most adult athletes need at least 7–9 hours of sleep, and with large training volumes even more; expert recommendations also advise a stable schedule, a cool dark bedroom and limiting caffeine in the second half of the day (Walsh et al., 2021). A daytime nap can be a useful addition but not a replacement for night sleep.
The third is adequate nutrition. The energy value of the diet must cover the expenditure on training and the body's basic needs. A chronic calorie deficit, especially in sports with weight categories or aesthetic demands, is a direct path to relative energy deficiency (Mountjoy et al., 2023). Also important are a sufficient amount of carbohydrates during periods of intense work and sources of iron in the diet.
The fourth is managing stress outside sport. Study, work, family events and sleep deprivation add up with the training load. During tense periods of life it is sensible to deliberately reduce training volume rather than add to it.
- gradual increase in load and regular unloading weeks;
- a stable sleep routine, limiting caffeine in the evening;
- a diet without a chronic energy deficit;
- returning to training after illness in stages;
- accounting for everyday and psychological stress.
Self-monitoring: what to track daily
The simplest and at the same time most informative tool is a wellbeing diary. A systematic review showed that subjective self-reports (mood, feeling of fatigue, sleep quality, muscle soreness) respond more sensitively to changes in load than many common objective indicators (Saw et al., 2016). It is enough to rate a few parameters each morning on a scale from 1 to 5.
It is also useful to record perceived exertion after each workout and the duration of the session. The product of these values gives a simple estimate of the training load, from which sharp jumps in weekly volume become visible.
Many athletes use resting heart rate and heart-rate variability, measured in the morning. These indicators make sense only as a trend over weeks for a specific person; a single "bad" value means nothing. A prolonged decline in variability together with poor wellbeing is a signal to review the load.
Finally, it is worth tracking results in standard tests: time over a known distance, power on a test segment, working weight in basic exercises. A steady decline in results despite training is one of the key criteria of overreaching.
Diagnosis at the doctor's: examination and tests
Diagnosis of chronic fatigue begins with a conversation. The doctor establishes the duration of symptoms, the link with training, the sleep routine, nutrition, past infections, psychological state, and also all medications, supplements and drugs the person has taken. Frankness about stimulants, hormones or anabolic steroids is critically important here, because they directly change both wellbeing and test results.
Next, a physical examination and basic laboratory tests are carried out. There is no universal "fatigue test": overtraining syndrome, for example, is diagnosed by excluding other causes, because there is no specific marker for it (Meeusen et al., 2013).
Particular attention in athletes is paid to iron status. Ferritin reflects iron stores, and its decline may precede anaemia; it must be interpreted taking inflammation into account, because ferritin rises as an acute-phase protein (Sim et al., 2019).
If needed, the examination is expanded: ECG, echocardiography, exercise tests, consultations with an endocrinologist, cardiologist, psychotherapist. If symptoms last more than six months and have no explanation, the doctor may consider a diagnosis of chronic fatigue syndrome in line with modern criteria (Institute of Medicine, 2015).
| Test | What it helps to detect |
|---|---|
| Complete blood count | Anaemia, signs of infection or inflammation |
| Ferritin, serum iron | Iron deficiency without anaemia |
| TSH, free T4 | Hypothyroidism or hyperthyroidism |
| Glucose, HbA1c | Disorders of carbohydrate metabolism |
| Liver and kidney panels, electrolytes | Organ dysfunction, electrolyte losses |
| Vitamin D, B12 (as indicated) | Deficiency states |
| Sex hormones (as indicated) | Hypogonadism, cycle disturbances |
When to see a doctor
It is worth seeing a doctor on a routine basis if fatigue lasts longer than two or three weeks despite reduced load, if results steadily decline, sleep or the menstrual cycle is disrupted, or frequent colds appear.
Seek help immediately in case of pain or pressure in the chest during exercise, fainting, pronounced shortness of breath, a feeling of heart irregularities, and also with rapid unexplained weight loss, persistent fever, night sweats or jaundice.
Separately, the editorial team stresses: if fatigue has appeared while taking, or after withdrawal from, anabolic steroids, thyroid hormones, clenbuterol or other weight-loss drugs, this must be told to the doctor directly. Such substances can cause hormonal and cardiac disturbances that require specialised treatment.
It is also unwise to delay if fatigue is accompanied by a persistently low mood, loss of interest in usual activities or thoughts of self-harm. This is a reason to see a doctor or psychologist as soon as possible.
Editorial conclusions
Prevention of chronic fatigue consists of simple but systematic steps: gradual load, planned rest, sufficient sleep and full nutrition.
Daily self-monitoring of wellbeing, perceived exertion and test results helps to spot the problem at an early stage, when a few days of unloading are enough.
If rest does not help or warning symptoms appear, a medical examination is needed: blood tests, assessment of iron, thyroid, heart and hormones.
We also recommend reading our materials on the causes of chronic fatigue in athletes, on the prevention of overtraining and on the ferritin test.
References
- 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):186–205.
- Saw AE, Main LC, Gastin PB. Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures: a systematic review. Br J Sports Med. 2016;50(5):281–291.
- Walsh NP, Halson SL, Sargent C, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. Br J Sports Med. 2021;55(7):356–368.
- Mountjoy M, Ackerman KE, Bailey DM, et al. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). Br J Sports Med. 2023;57(17):1073–1097.
- Sim M, Garvican-Lewis LA, Cox GR, et al. Iron considerations for the athlete: a narrative review. Eur J Appl Physiol. 2019;119(7):1463–1478.
- Institute of Medicine. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington (DC): National Academies Press; 2015.
- Halson SL. Monitoring training load to understand fatigue in athletes. Sports Med. 2014;44(Suppl 2):S139–S147.
Andriy Melnyk
A strength-sports coach and author of programs for beginner and intermediate levels. Writes about training planning.
