Orthostatic intolerance as a potential contributor to prolonged fatigue and inconsistent performance in elite swimmers.

Observed Findings

• All five elite swimmers with fatigue and underperformance showed symptoms when subjected to orthostatic testing (passive standing or tilt table).
• Two of the five swimmers met heart rate criteria for postural tachycardia syndrome (POTS).
• All five swimmers experienced prompt improvement in fatigue and orthostatic symptoms after treatment with increased sodium chloride and fluid intake.
• All five swimmers were able to return to their expected performance level or improve their practice consistency following treatment.
• Orthostatic testing reliably provoked fatigue and other symptoms in all participants.

Inferred Conclusions

• Orthostatic intolerance is an easily measured and treatable contributor to athletic underperformance in at least some athletes with fatigue.
• Formal orthostatic testing (passive standing tests or tilt table tests) should be incorporated into clinical evaluation of athletes presenting with fatigue and underperformance.
• Simple interventions targeting orthostasis (sodium and fluid replacement) may provide significant functional improvement in some underperforming athletes.
• Orthostatic intolerance should be considered alongside other potential causes such as overtraining syndrome and ME/CFS when evaluating athletes with persistent fatigue.

Remaining Questions