Drink at least half your body weight in ounces of water a day, and use urine color as your gauge: clear may mean you're overdoing it relative to your electrolytes, pale yellow means you're on track, dark means drink more (and get it checked if you see blood).

noli's read

The strongest part of this post is the urine-color gauge: it traces back to Armstrong et al.'s foundational 1994 paper (International Journal of Sport Nutrition), and later validation studies find decent diagnostic accuracy (AUC 0.74-0.96 depending on the study) for spotting hypohydration, especially after exercise in the heat. Near-colorless urine alongside very high water intake can genuinely reflect a relative electrolyte dilution, and dark urine remains a reliable under-drinking signal — so the color check holds up. The 'at least half your body weight in ounces' rule, though, is a fitness-world shortcut, not an official guideline: the Institute of Medicine's figures (echoed by Mayo Clinic and Harvard Health) put total daily fluid at roughly 2.7L for women and 3.7L for men, food and other drinks included — and a registered dietitian quoted by Banner Health explicitly rejects both 'half your body weight in ounces' and 'eight glasses' as formulas with no dedicated evidence behind them. The 'clear urine means you're losing electrolytes' framing is physiologically plausible but is an inference, not a direct study finding. Telling people to seek care for blood in urine is sound, unrelated safety advice. Verdict: mixed — the urine gauge holds, the ounces formula is a mnemonic convenience, not validated data.

the sources

1. 1Valtin H 2002