Overtraining Syndrome in Swimming: Immunosuppression from Frequent Training and Recovery Strategies

Introduction

Many dedicated swimming enthusiasts and junior competitive athletes in Taiwan approach training with a “more is better” mindset. Especially under the school examination system, many parents and coaches believe that high training volumes are the only way to secure athlete quotas, making overtraining a common occurrence in Taiwan’s swimming community.

Overtraining Syndrome (OTS), also known as Non-Functional Overreaching (NFOR), refers to a pathological adaptation that occurs when training stimuli continuously exceed the body’s recovery capacity, leading to long-term performance decline and comprehensive deterioration of physical and mental state. It is not a badge of effort, but a serious warning signal from the body.

Diagnostic Criteria for OTS

There is no single “definitive test” for OTS; it is typically diagnosed through a combination of symptoms plus the exclusion of other diseases. The following is a commonly used assessment framework:

Primary Symptoms

Symptom Category	Specific Manifestations
Performance Decline	Performance continuously regresses for > 2 weeks at the same training intensity
Fatigue	Fatigue persists even after adequate sleep; morning resting heart rate increases by > 5 bpm
Mood and Cognition	Irritability, anxiety, depression, decreased concentration, loss of motivation
Immune Abnormalities	Recurrent upper respiratory infections, oral ulcers, slower wound healing
Sleep Disturbances	Difficulty falling asleep, excessive dreaming, early awakening, decreased sleep efficiency
Musculoskeletal	Muscle soreness lasting more than 72 hours, increased risk of stress fractures
Hormonal Abnormalities	Amenorrhea in females (Female Athlete Triad), decreased libido, elevated cortisol

Severity Classification of OTS

• Functional Overreaching: Short-term fatigue accumulation, fully recoverable with 1–2 weeks of rest; part of a normal training cycle
• Non-Functional Overreaching (NFOR): Requires weeks to months to recover; noticeable performance decline
• Overtraining Syndrome (OTS): Requires systematic recovery spanning months to over a year; a severe condition

Impact on the Immune System

Long-term overtraining damages the immune system on multiple levels:

• Decreased Secretory Immunoglobulin A (sIgA): sIgA is the first line of defense for mucosal immunity in the respiratory and digestive tracts; studies show that saliva sIgA concentrations in OTS swimmers drop by 40–60%, explaining why overtrained athletes are particularly prone to colds
• Reduced Natural Killer (NK) Cell Activity: Lowers defense against viral infections
• Chronically Elevated Pro-inflammatory Cytokines (IL-6, TNF-α): Sustained low-grade inflammation impairs tissue repair
• Cortisol/Testosterone Ratio (C/T ratio) Imbalance: A characteristic hormonal marker of OTS; elevated cortisol and decreased testosterone continuously suppress muscle anabolic metabolism

Systematic Recovery Strategies

Training Adjustments

• Immediate Volume Reduction: After an OTS diagnosis, training volume should be reduced by 50–80%, with intensity lowered to RPE < 11 (very light)
• Complete Rest Period: Severe OTS may require 2–4 weeks of complete training cessation to allow the neuroendocrine system to reset
• Progressive Retraining: During recovery, follow the low-intensity principle of “heart rate not exceeding resting heart rate + 40 bpm”

Sleep and Recovery

• 8–10 hours of high-quality sleep per night is the foundation of hormonal recovery
• 30–60 minutes of daytime rest (not mandatory, but beneficial for recovery)
• Avoid using 3C devices 2 hours before bedtime to reduce blue light interference with melatonin

Nutritional Support

• Adequate Caloric Intake: OTS patients often present with Low Energy Availability (LEA); ensure sufficient daily caloric intake
• Carbohydrate Supplementation: Consume carbohydrates (0.5–0.8 g/kg) within 30 minutes after high-intensity swimming to reduce cortisol peaks
• Vitamin C and E: Provide antioxidant protection and reduce training-induced immune suppression
• Probiotics: Improve gut barrier function and indirectly enhance mucosal immunity

Psychological Support

• OTS is often accompanied by low mood and even athletic burnout
• University physical education departments and sports medicine centers across Taiwan offer sports psychology counseling services
• Cognitive Behavioral Therapy (CBT) has shown good efficacy for the psychological components of OTS

Prevention Strategies

• Use RPE logs or HRV monitoring: Record daily post-training perceived exertion ratings (1–10) and morning resting heart rate variability to detect early signs of insufficient recovery
• Schedule regular deload weeks: Every 3–4 weeks, incorporate a deload week with training volume reduced by 30–40%
• Limit weekly training volume increase rate: Do not exceed 10% over the previous week
• Establish a rest-day culture: Take at least 1–2 complete rest days per week; do not force “light training” as a substitute

Practical Recommendations

1. Parents of young competitive swimmers in Taiwan should pay special attention to whether their children exhibit the triad of declining performance + low mood + frequent colds
2. Coaches can use a “training volume–performance” tracking chart; if training volume increases but performance does not improve, OTS should be ruled out first
3. Utilize sports medicine departments across Taiwan for hormonal marker testing (cortisol/testosterone ratio, IGF-1) to help objectively assess OTS severity
4. OTS recovery cannot be forced through “willpower”; this is a physiological issue, and rest is the best training
5. Coaches and athletes should build a strong communication and trust relationship so that athletes feel comfortable expressing fatigue—this is the most fundamental mechanism for preventing OTS

Conclusion

Swimming is a beautiful sport, but beauty should be cherished, not consumed. Overtraining syndrome teaches us that the purpose of training is stimulation, while recovery is where progress actually happens. Learning to listen to your body and finding your own balance between effort and rest is the true path to excellence.

Related Reading

• Identifying, Preventing, and Fully Recovering from Overtraining Syndrome (OTS)
• Recognizing Overtraining Syndrome (OTS) and Planning a Return-to-Training Program
• Identifying Swimming Overtraining Injuries: Risk Management for Rapidly Increasing Training Volume
• Youth Sports Injury Prevention: Identifying and Preventing Overtraining Syndrome