Best Electrolytes for Hyrox and Other Indoor Races: Sodium First

The best electrolyte for an indoor race like Hyrox is the one built around sodium — not potassium, not vitamins, not flavour. Arenas are warm and humid, you sweat for the whole 75–120 minutes, and sodium is the electrolyte you lose in by far the largest amount. Below: how to read a label so you can tell a sodium-led formula from a flavoured vitamin drink, which product format suits which moment of race day, and the picks we hand to Hyrox athletes across stick packs, tubs, liquid concentrates and carb-plus-electrolyte mixes.

Key Takeaways

• Sodium is the electrolyte that matters for a 60–120 minute indoor race. Heavy or salty sweaters should look for several hundred milligrams up to about a gram per serving; light sweaters can sit lower.
• Read the panel: in Canada sodium often appears in the non-medicinal ingredients as sodium citrate or salt, sometimes without a milligram figure. If a product headlines potassium and magnesium, it is not a race electrolyte.
• Match the format to the moment: stick packs for the start corral, a tub for daily training, a liquid concentrate for any bottle, a carb-plus-electrolyte mix for long simulations.
• Drinking large volumes of plain water without sodium is a real mistake in this event. Drink to thirst and put sodium in some of it.
• Race-day pattern: one full serving with dinner the night before, 250–500 mL in the last 15 minutes, sips at the stations, one full serving in the recovery shake.

Why Indoor Races Are Harder on Hydration Than Outdoor Ones

A road race has wind, shade and cooler air; a Hyrox venue has none of them. Exhibition halls sit at room temperature or above, humidity climbs as a few thousand athletes work through the day, and there is no airflow over your skin to evaporate sweat efficiently, so you sweat more and cool less. Add the fact that you are alternating running with heavy pushing and carrying — which spikes heart rate above what a steady run would — and sweat rates in Hyrox are routinely higher than athletes expect from their outdoor training. Over 90 minutes that can mean well over a litre of sweat and a meaningful amount of sodium. That is the reason electrolytes made the shortlist in our pillar guide to Hyrox supplements even though the race is not especially long.

How to Read an Electrolyte Label (Canadian Edition)

Canadian supplement panels split ingredients into medicinal (with milligram amounts) and non-medicinal (often without). Many electrolyte products list potassium and magnesium under medicinal ingredients with tidy numbers — and put the sodium in the non-medicinal list as “sodium citrate” or “salt,” sometimes with no figure at all. The Magnum REFRSH panel is a clear example: 200 mg potassium and 170 mg magnesium declared, with sodium citrate and salt present but not quantified. That is not a flaw in the product; it is how the format works. It does mean you should look for sodium first and, where a brand does state it, prefer the one that tells you the number.

What counts as enough? For a heavy or salty sweater — white streaks on a black shirt, stinging eyes — several hundred milligrams up to around 1,000 mg of sodium per serving is the range worth aiming for around the race. A lighter sweater can sit lower. Potassium and magnesium are fine to have, but a product that leads with them and treats sodium as an afterthought is a daily wellness drink, not a race electrolyte. Sugar is not automatically bad here either: a few grams of carbohydrate helps the fluid absorb, and during the race it doubles as fuel.

Format Comparison: Which Electrolyte for Which Moment

Your Race-Day Hydration Plan

The night before: one full electrolyte serving with dinner and slightly saltier food than usual. Starting the day sodium-loaded is easier than catching up mid-race. 15 minutes before your wave: 250–500 mL of electrolyte drink — enough to be topped up, not so much that it sloshes on the SkiErg. During: Hyrox provides water at set points; sip rather than gulp, and if you carry your own bottle, make it electrolyte rather than plain water. Your gels or chews are supplying carbohydrate; the drink’s job is sodium. After: a full serving in or alongside your recovery shake, and keep drinking to thirst for the rest of the day. The race-week nutrition plan places all of this in the wider seven-day picture.

Two cautions. First, do not over-drink plain water in the hours before the race in an attempt to “pre-hydrate”; without sodium it dilutes blood sodium and can leave you feeling flat, nauseous or worse. Second, if you cramp readily, the answer is usually more sodium earlier — the night before and at the start — rather than more fluid during. Athletes who cramp at wall balls almost always under-salted the day before.

Training-Day Hydration Is Where You Learn Your Sweat Rate

The cheapest piece of race-day data you can collect is your sweat rate: weigh yourself before and after a hard 60-minute indoor session, add back whatever you drank, and the difference in kilograms is roughly your litres of sweat per hour. Most Hyrox athletes are surprised by the number. Use a tub electrolyte through the training block so the habit is built and you know how your stomach responds, then switch to stick packs for race day. If your sweat leaves white marks on dark kit, move toward the extra-strength formulas and salt your food more; if it does not, the standard strength is enough. Everything here is in the hydration section of the Best Supplements for Hyrox Athletes collection.

Our Picks for Indoor Race Hydration

Frequently Asked Questions

Do I really need electrolytes for a race that only lasts about 90 minutes?

For most Hyrox athletes, yes. The race is indoors, warm and humid, and mixes running with heavy work, so sweat rates are higher than a 90-minute outdoor run. Sodium replacement before, during and after is a small cost that removes a common cause of a bad second half.

How much sodium should an electrolyte have for Hyrox?

Heavy or salty sweaters should look for several hundred milligrams up to about 1,000 mg per serving around the race; lighter sweaters can use less. Check the panel — sodium is often listed under non-medicinal ingredients as sodium citrate or salt.

Are electrolyte tablets or powders better?

Either works; the difference is convenience. Stick packs and tablets suit race day and travel, tubs suit daily training at a lower cost per serving, and liquid concentrates let you add electrolytes to a drink you already like.

Can I just drink a sports drink instead?

A conventional sports drink provides carbohydrate and a little sodium — usually less than a dedicated electrolyte mix. It is a reasonable option at the water stations, but for the night before and the start corral a sodium-led electrolyte does the job better.

Should I take electrolytes every day during training?

On hard indoor sessions and hot days, yes; on easy days, food and water are usually enough. Using a tub through your block also teaches you how your stomach handles the product before race day.

What causes cramping at the wall balls, and will electrolytes stop it?

Cramping is multi-factorial — fatigue, pacing and heat all contribute — but under-salting the day before is the most common and most fixable piece. A full electrolyte serving with dinner and another before the start is the first thing to try.

Sources and Further Reading

• Best Supplements for Hyrox Athletes: Fuel, Hydrate, Lift and Recover — our pillar guide to the four supplement jobs Hyrox creates
• Precision Fuel & Hydration — how to fuel and hydrate a HYROX competition
• GoodLife HYROX Toronto 2026 — official event page

This guide is general information for healthy adults and is not medical advice. Check with a healthcare practitioner before adding supplements if you are pregnant, nursing, taking medication or managing a health condition, and always follow the directions on the product label.