The community suggests that to avoid bathroom breaks during a race, one should front-load hydration in the preceding days rather than the morning of, limit bladder-irritating beverages (coffee, concentrated electrolytes, acidic drinks) before the start, and accept that urgency is sometimes a fleeting sensation linked to stress or irritation rather than an actual need.

noli's read

The community converges on a cautious management of pre-race intake, highlighting the irritating nature of certain beverages. The idea that electrolytes and caffeine increase urgency is supported by physiology: caffeine can stimulate bladder motility (International Urogynecology Journal) and high solute concentrations can alter diuresis. However, the advice to eliminate all fluid intake is risky, as excessive dehydration can impact performance. The explanation regarding bladder irritants is consistent with standard clinical recommendations, but the idea that one can simply 'run through' the urge is an empirical strategy, not validated by research, which depends on individual tolerance. It is important to note that pre-competition anxiety physiologically triggers frequent bladder voiding, a phenomenon well-documented in sports psychology, regardless of hydration. Finally, the assertion that urine is sterile is a myth largely refuted by modern microbiology, although this does not impact race performance.

the sources

1. 1Valtin H 2002
2. 2r/AdvancedRunning