What is Overtraining Syndrome?

Overtraining syndrome (OTS), also called paradoxical deconditioning syndrome or unexplained underperformance syndrome, refers to the sports-specific decrease in performance that occurs as a result of excessive overloading combined with insufficient recovery. In addition to performance decrements, athletes experience various neurologic, hormonal, immunologic, and psychologic disturbances. Unlike functional over-reaching (FOR), which is classified as a temporary decrease in performance followed by improvements after adequate recovery, OTS occurs as a result of non-functional overreaching (NFOR) that does not result in improvements in performance, even after months of recovery (Meeusen et al., 2013). Contrary to popular belief, OTS doesn't just occur in elite-level athletes. Recreational athletes are just as susceptible, or potentially even more susceptible to OTS as elite athletes. Data on OTS in the recreational athletic population is lacking, but because these athletes generally do not have coaches and may not be aware of the risk factors of OTS, it's possible that they may be at an increased risk of developing OTS.

Risk factors of OTS include poor sleep quality, inadequate caloric, carbohydrate, and protein intake, psychological stress, and excessive work or study hours (Cadegiani & Kater, 2021). Monotonous training and too many competitions may also contribute to OTS.

The pathophysiology of OTS is not well-understood; however, there are many proposed underlying mechanisms such as inflammation, oxidative stress, autonomic nervous system dysregulation, and hypothalamic dysregulation. The historical treatment for OTS is rest, although more recent approaches have taken diet, sleep, and stress into consideration.

Symptoms

Symptoms of OTS may present differently depending on the sport. In aerobic sports (e.g., running, cycling, swimming, mountaineering) parasympathetic alterations may be seen, including fatigue, depression, bradycardia, and loss of motivation. In anaerobic sports (e.g., strength training, HIIT, sprinting), sympathetic alterations are more common and may include insomnia, irritability, agitation, tachycardia, hypertension, and restlessness. Other symptoms may include anxiety, frequent injuries, frequent upper respiratory tract infections, increased resting heart rate, weight loss, increased body fat percentage, decreased muscle mass, lack of concentration, and heavy, stiff, sore muscles. (Kreher, 2012).

Diagnosis

There are currently no definitive biomarkers or diagnostic tools for diagnosing OTS; instead, diagnosis relies on the exclusion of confounding conditions such as thyroid and adrenal disorders, diabetes, iron deficiency, and infections (Meeusen et al., 2013). Nevertheless, various biomarkers have been identified that may be helpful in the prevention and early detection of OTS. According to Cadegiani & Kater (2021), useful markers in the detection of OTS include altered cortisol awakening response (CAR), estradiol, testosterone:estradiol ratio, nocturnal urinary catecholamines, noradrenaline, dopamine, creatine kinase, neutrophil count, and neutrophil:lymphocyte ratio. Altered oxidative stress markers like GSH:GSSG ratio have also been observed in this population. Heart rate variability (HRV) may prove to be a useful tool in the future; however, there is currently a need for HRV data in overtrained and overreached athletes.

Interventions

Dietary and lifestyle interventions are fundamental to OTS recovery and include addressing caloric intake, carbohydrate intake, and protein intake, addressing sleep disturbances, effectively managing stress and cognitive demands, and modifying training load. In a 12-week intervention study (Cadegiani and Kater, 2021), participants adhered to dietary modifications, training modifications, sleep interventions, and stress management. Dietary modifications included increasing total caloric intake, carbohydrate intake, and protein intake. Participants were also encouraged to have two ad libitum meals per week. For the sleep intervention, participants made improvements to sleep hygiene and were instructed on how to maintain strict self-control on the timing and duration of sleep, although it’s unclear how the intervention was implemented and how adherence was monitored during the 12-weeks. For the stress intervention, stress management techniques were implemented while instructing athletes to limit excessive cognitive demands. Psychotherapy was used when appropriate. Similar to the sleep interventions, it’s unclear how these interventions were implemented and how adherence was monitored. Despite these shortcomings, significant improvements in biochemical markers like estradiol, testosterone, testosterone:estradiol ratio, cortisol awakening response, nocturnal urinary catecholamines, creatine kinase, IGF-1, and free T3 were observed after the 12-week intervention.

Other interventions that have not been researched extensively but may have some use in the management and prevention of OTS include multivitamin/mineral supplements, omega-3 fatty acids, vitamin D, and L-glutamine. In addition, possible associations between gut microbiota and overtraining syndrome are likely to be explored in the future.

Steps you can take to avoid overtraining syndrome:

1. Eat enough high-quality food to fuel and recover from your workouts. Inadequate caloric intake is a risk factor for OTS. Failing to eat enough to meet the demands of your workouts can not only hinder your performance, but can increase inflammation, put you at risk for overtraining, and can cause hormonal and immune system imbalances, especially in females.

2. Get enough high-quality sleep to help you recover from your day. Aim for around 8 hours of sleep each night.

3. Find ways to effectively manage stress. Stressful situations are oftentimes outside of our control; however, meditation, progressive muscle relaxation, deep breathing, taking a walk in nature, and finding time for your favorite hobbies are some ways you can help improve how you perceive and respond to stress.

4. Mix up your training routine and don't commit to too many competitions in one season.

5. Increase your training volume and intensity slowly. Increasing activity too quickly can increase your chances of injury and overtraining. The general rule of thumb is to increase your activity (intensity, distance, time, amount of weight lifted, etc.) by no more than 10% each week.

6. Consider hiring a coach, nutritionist, or other qualified healthcare professional who is trained to know the signs and symptoms of overtraining syndrome and who can help you come up with a solid nutrition and lifestyle plan to support your training. Always seek the advice of your medical doctor if you think you have overtraining syndrome or any other illness.

References

Cadegiani, F. A., Silva, P. H. L., Abrao, T. C. P., & Kater, C. E. (2021). Novel Markers of Recovery From Overtraining Syndrome: The EROS-LONGITUDINAL Study. International Journal of Sports Physiology & Performance, 16(8), 1175–1184.

Kreher, J. B., & Schwartz, J. B. (2012). Overtraining syndrome: a practical guide. Sports health, 4(2), 128–138.

Meeusen, R., Duclos, M., Foster, C., Fry, A., Gleeson, M., Nieman, D., Raglin, J., Rietjens, G., Steinacker, J., & Urhausen, A. (2013). 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). European Journal of Sport Science, 13(1), 1–24.