Electrolyte powders

电解质粉

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汗液里到底丢什么 · 谁真正需要 · 日常水营销拆穿

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Recovery science
1 L sweat ≈ 1 g sodium loss. Sub-1h training: daily diet (3-5 g/day) already covers; >2h or hot conditions: 300-700 mg Na/L drink. Exercise-associated hyponatremia (EAH) is a real, occasionally fatal risk.

What's actually in sweat

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汗液里到底丢什么

Sweat isn't just water — it's dilute extracellular fluid, with enormous individual variation. Pin down the skeleton data first; all judgements downstream rest on it.

Main sweat electrolytes (mmol/L, approximate ranges):

Ion	Median	Range
Na⁺ (sodium)	~40	20–80 (high-sweat-sodium phenotypes 90+)
K⁺ (potassium)	~5	3–10
Cl⁻ (chloride)	~40	20–80
Ca²⁺	~1	0.5–2
Mg²⁺	~0.2	0.1–0.4

Conversion in practice: one hour of heavy sweating (~1 L) typically loses:

~900 mg sodium (40 mmol), equivalent to 2.3 g of salt (NaCl)~200 mg potassium~5 mg magnesium (negligible)~40 mg calcium (negligible)
Key insight: the most important sweat electrolytes are sodium and chloride; the rest is essentially decoration. So the core question of any 'electrolyte supplement' is always: how much sodium did you actually lose, and how much have you already replaced from food and water?

Sweat sodium concentration varies between individuals:

'Salty sweater' (high-sweat-sodium, >60 mmol/L): visible white salt streaks on clothing, salty skin after training'Light sweater' (<30 mmol/L): no visible salt streaksCombined result of genetics (CFTR gene variants etc.) and adaptationHeat-acclimation training (10–14 days) can lower sweat sodium concentration ~50% — the body learns to conserve salt
So for the same 1 hour of exercise, 'salty + unadapted' vs 'light + heat-adapted' can differ in sodium loss by 4–5×.

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Educational content, not medical advice — consult a clinician.

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