excuse my lack of bio/physiology knowledge but what’s performance enhancing about peeing a lot?
4 reasons.
1) fighters (boxing, martial arts etc) compete in weight categories, pissing out half a stone and alsmot passing out through dehydration is the order of the day at weigh in (after which you can drink litres of water and hit the gym again). Less relavent to cyclists
2) Dilutes your pee, if they’re looking for a concentration of something then diluting your pee puts it under the threshold.
3) can be used to selectively remove things from your blood into pee based on pH, so if your performance enhanceing drug is acidic, and you take a diuretic that excreets alkali’s preferentialy they wont show up in urine samples.
4) Flushes drugs out of the day before testing, so on the eve of the TDF take some diuetics and drink gallons of water and the past 6 months drug use is washed through.