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How Much Salt Is Safe: WHO Guidelines and Why It's More Complicated for Athletes

The WHO advises eating less than 5 g of salt a day, but during a multi-hour race in the heat that rule works in reverse. Let's figure out how to reconcile both approaches without harming your heart or cramping up on the course.

AS
Anna Severova

We add salt to our food almost without thinking, and then we run into two opposite pieces of advice. Your doctor and the WHO say: "eat less salt." A seasoned ultramarathoner at the pre-race briefing hands you salt capsules: "without sodium you'll drop out." Who's right? Strangely enough — both. These are simply two different scenarios that can't be measured with the same yardstick.

What the WHO Recommends and Why

The WHO recommendation for adults is simple: <2000 mg of sodium per day, which is equivalent to <5 g of salt — roughly one teaspoon. For children aged 2 to 15, the limit is adjusted downward to account for their energy needs.

A handy reference for reading labels: 1 g of salt ≈ 400 mg of sodium, which means 5 g of salt is exactly those 2000 mg of sodium. Packaging often lists sodium specifically, and it's easy to underestimate the real dose.

The problem is that in reality people eat far more salt. According to WHO estimates, the global average intake in 2021 was 4278 mg of sodium per day (about 11 g of salt) — more than double the recommendation. And a significant share of that sodium comes not from the salt shaker but from processed foods: bread, sausages and processed meats, snacks, and sauces.

Why Excess Is Dangerous

Chronic sodium excess means, first and foremost, elevated blood pressure, and through it, a rising risk of cardiovascular disease. The WHO also links high salt intake to stomach cancer, obesity, osteoporosis, Ménière's disease, and kidney disease.

The scale of the problem is serious: according to WHO estimates, in 2023 about 1.7 million deaths per year were linked to excess sodium intake. At the same time, cutting salt is one of the most cost-effective public health measures: every $1 invested yields at least $12 in return. That's exactly why the WHO set a goal of reducing population salt intake by 30% (originally by 2025, with the deadline extended to 2030).

Sport in the Heat Is a Different Context

And now for an important nuance that general recommendations stay silent about. The advice "eat less salt" is aimed at an ordinary person on an ordinary day — with the office, the couch, and moderate activity. Hours of exertion in the heat is an entirely different physiology.

With sweat you lose not only water but also sodium. On a long course — a marathon, an ultra, a bike ride, a triathlon — the losses can be significant, especially for those who sweat heavily and saltily (white streaks on your clothing are a telltale sign). If in this situation you drink only plain water and don't replenish sodium, your blood is literally "diluted": hyponatremia develops — a dangerously low sodium level. Its symptoms (nausea, confusion, swelling, cramps) are treacherous on the course because they resemble ordinary dehydration, yet the treatment is the exact opposite.

The key idea: the WHO recommendation is about your daily baseline diet at rest, not about your behavior during extreme exertion. The two don't contradict each other. Lowering your background salt in everyday life and adding sodium during a long race isn't a conflict — it's smart management across two different modes.

How to Apply This in Practice

  • On ordinary days, keep your baseline low. The main source isn't the salt shaker but processed foods. Fewer sausages, snacks, and ready-made sauces — and you're already close to the WHO target without any suffering.
  • Read labels by sodium, not "by eye." Remember the conversion: 400 mg of sodium = 1 g of salt.
  • Separate "everyday life" from "the race." Prolonged exertion in the heat is the one case where you deliberately add sodium: sports drinks, salt tablets, or salted drinks.
  • Don't flush away fatigue with plain water. On courses lasting several hours or more, water without electrolytes raises the risk of hyponatremia.
  • Test your strategy in training. Sweat rate and sodium losses are individual — dial in what works for you in calm conditions, not at the start of an important race.
  • Short, easy workouts count as "everyday life." An hour-long run in comfortable weather doesn't require extra salt; here the usual recommendations apply.

The Bottom Line

  • WHO: for adults — <2000 mg of sodium (<5 g of salt) per day; for children aged 2–15 the limit is lower.
  • In reality the world eats twice as much: ~4278 mg of sodium (11 g of salt) per day (2021).
  • Excess sodium raises blood pressure and is linked to 1.7 million deaths per year (2023).
  • Most salt comes from processed foods, not from the salt shaker.
  • General salt-reduction advice ≠ behavior during a multi-hour race in the heat: in everyday life we lower the baseline, in an ultra we replenish sodium to avoid hyponatremia.

Source: WHO — Sodium reduction. https://www.who.int/news-room/fact-sheets/detail/sodium-reduction

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