How Much Sodium & Electrolytes Do You Need? (2026 Guide)

By Erin Rose · Updated July 13, 2026 · Methodology

Educational summary of published guidance — not medical advice. If you have high blood pressure, kidney disease, or heart failure, or take diuretics or blood-pressure medication, talk to your doctor before adding sodium.

Electrolyte marketing has done something clever: it took a real need for a small number of people — endurance athletes, keto dieters, sick kids — and sold it to everyone. The science is genuinely interesting, but it does not say that a healthy person at a desk needs 1,000 mg of supplemental sodium. This guide sorts out who needs what.

How much, by situation

Normal day / light exercise — you're probably fine

If you eat a typical diet and exercise under about an hour at moderate intensity, plain water is generally enough. The ACSM/Academy of Nutrition and Dietetics position statement only recommends carbohydrate-electrolyte drinks for prolonged or intense exercise, heavy sweating, or heat (Thomas 2016, PMID 26891166). It never recommends them for people who aren't exercising. A daily electrolyte drink for a desk job is a preference, not a need — and the average diet already supplies more sodium than the 1,500 mg target.

Prolonged or intense exercise / heat — replace what you sweat

Sweat sodium varies enormously between people — roughly 460 to 2,300 mg per liter of sweat, and sweat rates run 0.5–2+ liters per hour (Baker 2017, PMID 28332116). That individual variability is the whole point: there is no single "correct" number, which is exactly what one-size sports-drink dosing gets wrong. A practical starting range is 300–600 mg of sodium per hour of hard exercise in heat, adjusted to how salty your sweat is (white salt marks on your kit = a high-sodium sweater). In a meta-analysis, a hypotonic carbohydrate-electrolyte drink produced somewhat greater central hydration than plain water or a more concentrated drink during continuous exercise (Rowlands 2022, PMID 34716905).

Keto, low-carb, or fasting — the mechanism is real, the dose is rough

Cutting carbs lowers insulin, and lower insulin makes your kidneys reabsorb less sodium, so you lose more in urine — a directly demonstrated effect of insulin on renal sodium handling (DeFronzo 1975, PMID 1120786). Low-carb clinicians commonly suggest replacing roughly 3,000–5,000 mg sodium/day, and "keto flu" symptoms are attributed to this loss. Be honest about the evidence: a survey documents the symptoms and the sodium theory (Bostock 2020, PMID 32232045), but controlled trials proving a specific sodium dose resolves them are lacking. Start at the low end and adjust — and skip the high sodium entirely if you have high blood pressure or kidney disease without medical sign-off.

Illness (vomiting / diarrhea) — this is where sugar earns its place

When you're losing fluid to illness, a glucose-paired oral rehydration solution (ORS) absorbs faster than water, because glucose and sodium are co-transported across the gut wall together, pulling water with them (Wright 2011, PMID 21527736). The reduced-osmolarity WHO ORS is the clinical standard and cut the need for IV fluids versus the older formula (Hahn 2002, PMID 11869639). This is the one everyday situation where a sugar-containing electrolyte drink is the right call — the sugar is functional, not a treat. For severe or persistent illness, especially in children, see a clinician.

Diagnosed POTS / low blood pressure — clinician territory

For postural orthostatic tachycardia syndrome, the Heart Rhythm Society consensus does recommend markedly increased sodium (around 10–12 g of salt/day, roughly 4,000–5,000 mg sodium) plus 2–3 liters of fluid — but explicitly as physician-supervised symptom management for a diagnosed condition, not a general wellness dose (Sheldon 2015, PMID 25980576). If this is you, your target comes from your cardiologist, not a calculator.

The sodium controversy (why guidelines and marketing disagree)

You'll see two camps. Public-health guidance says keep sodium low: a Cochrane meta-analysis confirms modest salt reduction lowers blood pressure (He 2013, PMID 23558162). But the large PURE cohort found a J-shaped curve, where both very low and very high sodium were associated with higher cardiovascular risk, with the middle (~4–6 g/day) looking safest (O'Donnell 2014, PMID 25119607). This is genuinely unresolved. The practical takeaway isn't "salt is good" or "salt is bad" — it's that context decides: a sedentary person with high blood pressure and a keto athlete in the heat are not the same case, and no electrolyte brand's blanket "you need more salt" message accounts for that.

Frequently asked questions

Related

• Electrolytes: the full guide — what they are, who needs them, and how the products compare
• Best electrolyte drinks — every product ranked by verified sodium, cost, and certification
• Formulas compared + DIY recipe — pick by use case, or make your own for pennies
• Magnesium dosage guide — most electrolyte drinks are low in magnesium

Sources