Most hydration advice is a rule of thumb. We read the research, show the sources, and explain what can actually be measured, what is only estimated, and what nobody knows yet.
Urine color charts: what they can tell you, and what they can't
The chart taped inside every locker room bathroom is based on real research. It's also easy to misread.
How to measure your sweat rate with a bathroom scale
One litre of water weighs one kilogram. That single fact turns a cheap scale into the most accurate hydration tool most athletes will ever own.
How much water do you actually need?
Not eight glasses. The official numbers are higher than that, they include food, and they were never meant as a target for you personally.
Electrolytes: who actually needs them?
Some athletes lose nearly four times as much salt in their sweat as others. Most people on most days don't need a powder at all.
Drink to thirst or drink to a plan? What both camps get right
The loudest argument in hydration has two sides with real evidence. Neither side has the data that would settle it for you.
Can your smartwatch tell how much you sweat?
A 2025 study tested watch sweat-loss estimates against a scale. They followed the trend well and missed the amount by a lot.