Standardised Evaluation of Immunological Stress

Standardisierte Evaluation von Symptomen und Zeichen belastungsinduzierter und infektbasierter immunologischer Stressregulation

Two Pathways of Immunological Stress — click to expand
Exercise-Induced Stress
Belastungsinduziert
TriggerMechanical load, catecholamines, cortisol
OnsetAcute, load-dependent, reproducible
HallmarkLymphocytosis → lymphopenia; ↑NK cytotoxicity; neutrophilia
HormonesAdrenaline (SNS), cortisol (HPA)
ResolutionAdequate rest and nutrition; <24 h (acute)
Infection-Based Stress
Infektbasiert
TriggerPathogen recognition via PRRs/PAMPs, cytokine cascade
OnsetVariable, often insidious, not load-related
HallmarkFever, persistent neutrophilia, ↑CRP, ↑IL-6, ↑TNF
HormonesIL-1, IL-6, TNF, IFN-α/β, cortisol
ResolutionPathogen clearance, immunological memory; days–weeks
Differential Diagnostic Comparison
Parameter Exercise-Induced Infection-Based
Muscle sorenessFocal, load-specificDiffuse, no load relation
FatiguePost-exertional; resolves with restPersistent; worsened by exertion
Resting HRMild ↑, load-dependent≥ +7 bpm above individual baseline
FeverAbsent≥ 37.5–38.5 °C
CRP< 5 mg/L (after moderate exercise)↑↑ often > 20 mg/L in ARTI
Lymphocytes↓ post-exercise; normalises <24 h↓↓ persistent; altered differential
NLR / SII / SIRITransient biphasic patternPersistently elevated
Performance lossFunctional, reversibleSystemic, prolonged
Neck-Check Decision Algorithm
Acute symptoms during training or competition?
Fever ≥ 37.5 °C, or below-neck symptoms,
or systemic features (myalgia, dyspnoea, lymphadenopathy)?
YES
STOP training
Medical evaluation required
Level 1 diagnostics
CBC · CRP · CK
NO — above-neck only
Reduce intensity ≤ 60% VO₂max
Monitor 24–48 h
Symptom-free after 48 h?
→ Gradual return to normal training
Validated Assessment Instruments — click for detail
WURSS-21 / WURSS-11
Wisconsin Upper Respiratory Symptom Survey
Quantitative 0–7 scale for cold/ARTI symptoms (sneezing, nasal congestion, sore throat, cough, headache, myalgia). Tracks severity + functional impact on sport. Supports the neck-check rule. Score ≥ 7/session → medical review.
Session-RPE × Duration
Internal Training Load Index
Athlete-perceived exertion (Borg CR10) multiplied by session duration in minutes. Acute:chronic workload ratio > 1.5 indicates immunological vulnerability. Enables weekly load monitoring without instrumentation.
TQR Scale (1–20)
Total Quality of Recovery
Mirror image of RPE applied to recovery. Score <13 indicates insufficient recovery → training load reduction advised. Combines sleep quality, nutritional recovery, mental recovery, and physical readiness.
POMS / POMS-Brief
Profile of Mood States
Detects characteristic overreaching/overtraining cluster: ↑tension, ↑depression, ↑anger, ↑fatigue, ↓vigour. Inversion of the healthy "iceberg profile" is a sensitive early marker. Overlaps with prodromal phase of acute infections.
DALDA
Daily Analysis of Life Demands for Athletes
Composite athlete stress questionnaire covering training load, sleep, nutrition, muscle soreness, mood, and life stress. Distinguishes sources of stress from symptoms of distress. Useful for longitudinal monitoring across both exercise and infection-related stressors.
Morning HR + HRV
Autonomic–Immune Tone Index
Morning resting HR ≥ +7 bpm above individual baseline is a sensitive early marker of both inadequate recovery AND subclinical infection. HRV (RMSSD) reduction reflects sympathetic dominance associated with both overtraining and early infection. Simple, non-invasive, daily monitoring.
Tiered Laboratory Diagnostic Approach — click level for tests
1
Level 1 — Screening Field & Practice
Indicated for any symptomatic athlete
  • Differential blood count: WBC, GRA, LYM, monocytes
  • Calculated indices: NLR, SII, SIRI
  • C-reactive protein (CRP) & ESR
  • Resting HR / HRV (autonomic–immune tone)
  • Urinalysis
  • Avoid sampling within 2 h of exercise (trace elements, NLR)
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2
Level 2 — Extended Diagnostics Indicated by Level 1
Level 1 abnormalities or persistent symptoms
  • Trace element panel: Se, SELENOP, total Zn, free Zn (fZn), Cu, Fe, ferritin, transferrin saturation — adjust for hemoconcentration (Alis method)
  • CK, AST/ALT, creatinine, LDH — muscle vs. hepatic/renal differentiation
  • Pathogen-specific serology / PCR where clinically indicated
  • Thyroid function (TSH) for chronic fatigue presentations
  • Troponin I/T if myocardial involvement suspected
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3
Level 3 — Specialised Immunology Persistent / Severe
Recurrent infections, prolonged symptoms, post-infectious sequelae
  • NK cell subpopulations (CD56⁺, CD16⁺) and cytotoxic function (in vitro)
  • T cell repertoire: CD4⁺/CD8⁺ ratio; memory, effector, senescent subsets
  • Complement factors C3, C4
  • Salivary IgA — validated marker of mucosal immunity / URTI susceptibility
  • Lymphocyte proliferation assay; oxidative burst (neutrophil function)
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Return-to-Sport Clearance — 5-Step Protocol
1
Minimum rest: 10 days post-diagnosis incl. ≥ 3 consecutive symptom-free days. Asymptomatic: ≥ 3 days rest after positive test.
2
Clinical exam: Vital signs · lymphatic system · cardiopulmonary auscultation · resting ECG · neuromuscular assessment
3
Level 1 labs: CBC, CRP, CK · Troponin if cardiac symptoms · Echocardiography if new cardiac finding
4
Graded return (5 steps, min. 24 h each): Rest → Light aerobic → Moderate aerobic → Sport-specific → Full training → Competition
5
Post-COVID / prolonged course: No progressive training programmes · Monitor for post-exertional malaise (PEM) · Specialist referral if indicated
Field Evaluation Checklist
Domain Tool Threshold / Action
WellbeingTQR scale (1–20)TQR < 13 → reduce load
URTI symptomsWURSS-11 (0–7/item)Score ≥ 7/session → medical review
Training loadSession-RPE × minAcute:chronic > 1.5 → caution
Resting HRMorning measurement≥ +7 bpm above baseline → rest
MoodPOMS briefIceberg inversion → overreaching alert
TemperatureOral / tympanic≥ 37.5 °C → rest; ≥ 38.5 °C → physician
Lab Level 1CBC, CRP, CKCRP > 5 mg/L + symptoms → referral
Trace elementsSe, Zn, Cu, FeInterpret relative to exercise timing
Puta C et al. (2025). Kompendium der Sportmedizin. doi:10.1007/978-3-662-68883-0  |  Simon R et al. (2026). J Trace Elem Med Biol 94:127828  |  Schwellnus M et al. (2022). Br J Sports Med.