Are cramps always due to a lack of salt?

No. Sodium can play a role in some runners, especially heavy sweaters in heat, but cramps are multifactorial and often linked to neuromuscular fatigue and too high a pace.

Is drinking more enough to avoid cramps?

Not necessarily, and drinking too much can even be counterproductive. Steady, appropriate hydration, with sodium if needed, is more useful than simply 'drinking more'.

What should I do when a cramp hits during a race?

Slow down, gently stretch the affected muscle and rehydrate if you can. Prevention (preparation, pace, hydration) remains more effective than managing it in the moment.

Hydration7 min

Why do I cramp during races?

Cramps during races are common and frustrating, but their cause is rarely single. Long blamed solely on a lack of sodium or water, they're now seen as multifactorial: neuromuscular fatigue, an over-ambitious pace, insufficient preparation, but also, in some runners, dehydration and electrolyte losses. This guide reviews the possible causes and what hydration can — and can't — change.

Where do cramps come from?

Two main hypotheses coexist. The first, neuromuscular, links cramps to fatigue in muscles worked harder than they're prepared for — typically when you start too fast or exceed your training. The second, hydration- and electrolyte-related, mainly concerns heavy sweaters and long efforts in heat, with significant sodium losses. In reality, the two often combine. Identifying your context (pace, heat, sweat) helps target the right response.

Reducing the risk during effort

On the nutrition side, two levers help when the hydration angle is at play: keep steady hydration and supply sodium on long or hot efforts, especially if your sweat is very salty. On the effort side, a controlled starting pace and preparation matched to the distance reduce neuromuscular fatigue. None of these is an absolute guarantee, but combined they lower the risk.

Common mistakes

Systematically blaming cramps on a lack of salt alone
Starting too fast relative to your training
Neglecting sodium on a long, hot effort when you sweat heavily
Overloading on plain water with no electrolytes
Testing a new anti-cramp strategy on race day

Practical checklist

Steady hydration before and during the effort
Sodium on long / hot efforts, especially heavy sweaters
Controlled starting pace matched to your preparation
Gradual distance build-up in training
Strategy tested beforehand, not improvised on race day

FAQ

Hydration7 min

Running hydration: water, sodium and electrolytes

Hydration isn't just drinking more: duration, heat and your sweat rate all matter.

Read the guide

Hydration6 min

Isotonic drink: what is it for?

An isotonic drink can combine hydration, electrolytes and carbs depending on the formulation and context.