Água Diária por kg

Daily water intake: 35 mL/kg rule

For adults, the working figure is 35 mL of water per kg of body weight per day: L/day = peso_kg × 0.035. So a 70 kg adult lands at roughly 2.45 L/day. Children follow the Holliday-Segar rule instead: 100 mL/kg for the first 10 kg, 50 mL/kg for the next 10 kg, and 20 mL/kg above 20 kg. Athletes tack on about 0.5–1 L for every hour of hard exercise. Pregnancy raises the target by around 0.3 L/day, lactation by about 0.7 L/day. And keep in mind that you don't drink all of it. Food covers 20–30% of your total water through fruit, soups and vegetables.

Applications and context

It shows up in clinical nutrition, sports hydration plans, paediatrics and geriatrics. Lose just 1% of body weight to hypohydration and both cognitive performance and endurance already start to slip. Drinking too much is rarely a problem, though in extreme cases it triggers hyponatraemia (low sodium), uncommon but serious and seen mostly in endurance athletes. For older adults with heart failure (HF), the physician sets a fluid cap and the 35 mL/kg rule goes out the window.

FAQ

Does coffee and tea count? They do. The old "diuretic" worry has been put to rest, and moderate caffeine actually adds to your net hydration. Alcohol is the one that genuinely dries you out.

Is 35 mL/kg valid for the elderly? As a starting point, yes. But check first for heart failure, kidney disease and diuretic medication. When any of those is in play, the doctor sets the limit.

What about hot climate or fever? Add 10–15% for each degree your body temperature climbs above 37 °C, then push it higher still if you're sweating, out in the sun, or training in the heat.