What this solves
Generic "drink 3–4 L a day" advice gets two groups into trouble on the Yading traverse: people who under-drink because the creek water tastes fine, and people who over-drink pure water because they're scared of dehydration — and end up with exercise-associated hyponatremia at 4,500 m. This tool blends your weight, exertion hours, altitude band, sweat rate and water source into a specific litre and salt target, with a sachet-by-hour schedule.
Build your hydration plan
How to read the result
Litres/day is your net drinking target — fluid that has to come out of bottles, not what's already in your food. Above 4,000 m the body loses an extra ~0.5 L/day through faster, deeper breathing. We add that to baseline sweat + exertion loss.
Sodium mg/day is built from a sweat concentration of 600 mg/L (mid ACSM range, conservative for trekking — not for athletes in heat). If you only drink plain water, you cannot meet this without dietary salt — that's the hyponatremia trap.
Sachet schedule tells you when to dose so plasma sodium doesn't crash. One sachet per 2 L is the floor. Below 3,500 m you can skip a sachet; above 4,500 m, take one every hour of effort.
Creek + iodine / Aquatabs is mandatory — Yading's runoff passes through yak pasture. Giardia in Sichuan streams is endemic. Bottled water only saves weight at Daocheng / Yading village; above 4,000 m you drink what's flowing.
Limitations
FAQ
A: Butter tea is high in fat and sodium, so it counts — but only if you drink a litre or more of it a day. Most trekkers drink one cup and then plain water. Plan for both.
A: Yes. Above the tree line you can often see yak dung within 50 metres of any flow. Giardia cysts are killed by boiling (≥ 1 min rolling boil), SteriPen, or Aquatabs (let it sit 30 min).
A: Above Yading village (3,700 m), not for a 5–day traverse — pack the first litre from town, refill from a treated creek after that. Inside the park gates, large bottles of Nongfu Spring are sold at Luorong, but they double in price.
A: Two common causes at altitude: you're still behind (drink an extra 500 mL/hour for 2 h) or the water source itself has diuretic compounds. Above Luorong, switch to bottled if you can find it.