How much sodium do you need during Hyrox?
Most people need little or no sodium during a Hyrox race, which takes most athletes 60 to 120 minutes, so DO IT's advice is to arrive well hydrated and get your sodium in the 2-4 hours before the start. If you start with normal sodium levels, you can usually finish without taking any on course.
Heavy, salty sweaters, people racing in hot venues, and anyone doing a double header or relay on top of other events can benefit from a planned sodium dose. The amount depends on how much you sweat and how salty your sweat is, and both vary a lot between people.
The short version
| Situation | Practical approach |
|---|---|
| Race under about 90 minutes, cool venue, normal sweater | Arrive hydrated. Water on course if thirsty. Sodium during the race usually isn't needed. |
| Race over about 90 minutes, or a hot venue | Consider a sodium-containing drink before the start and sips during. |
| Salty sweater (white salt marks on clothes, stinging eyes, cramp history in heat) | Plan sodium before and possibly during. Estimate your losses (below). |
| After the race | Replace fluid and sodium with normal meals and drinks. |
Race under about 90 minutes, cool venue, normal sweater
- Practical approach
- Arrive hydrated. Water on course if thirsty. Sodium during the race usually isn't needed.
Race over about 90 minutes, or a hot venue
- Practical approach
- Consider a sodium-containing drink before the start and sips during.
Salty sweater (white salt marks on clothes, stinging eyes, cramp history in heat)
- Practical approach
- Plan sodium before and possibly during. Estimate your losses (below).
After the race
- Practical approach
- Replace fluid and sodium with normal meals and drinks.
This follows the ACSM position stand on fluid replacement (Sawka et al., 2007): start exercise hydrated with normal plasma electrolytes, prevent losing more than about 2% of body weight from fluid during exercise, and replace deficits afterwards. The stand recommends individual plans because sweat rates and sweat sodium vary widely.
How to estimate your own sodium loss
You need two numbers: sweat rate and sweat sodium concentration.
1. Sweat rate. Weigh yourself (minimal clothing) before and after a hard 60-minute session that resembles race effort. Track what you drank.
Sweat rate (L/h) = (weight before - weight after in kg) + fluid drunk (L)
Example: 75.0 kg before, 74.2 kg after, drank 0.5 L. Sweat loss = 0.8 + 0.5 = 1.3 L in an hour.
2. Sweat sodium. Without a lab sweat test, use a population range. The ACSM position stand reports sweat sodium averaging about 35 mmol/L (roughly 800 mg per litre), with a wide range of about 10 to 70 mmol/L (roughly 230 to 1,600 mg per litre).
3. Multiply.
| Sweat lost | Low sodium sweat (about 230 mg/L) | Average (about 800 mg/L) | Salty sweat (about 1,600 mg/L) |
|---|---|---|---|
| 1.0 L | about 230 mg | about 800 mg | about 1,600 mg |
| 1.5 L | about 350 mg | about 1,200 mg | about 2,400 mg |
| 2.0 L | about 460 mg | about 1,600 mg | about 3,200 mg |
1.0 L
- Low sodium sweat (about 230 mg/L)
- about 230 mg
- Average (about 800 mg/L)
- about 800 mg
- Salty sweat (about 1,600 mg/L)
- about 1,600 mg
1.5 L
- Low sodium sweat (about 230 mg/L)
- about 350 mg
- Average (about 800 mg/L)
- about 1,200 mg
- Salty sweat (about 1,600 mg/L)
- about 2,400 mg
2.0 L
- Low sodium sweat (about 230 mg/L)
- about 460 mg
- Average (about 800 mg/L)
- about 1,600 mg
- Salty sweat (about 1,600 mg/L)
- about 3,200 mg
That's what you lose, not what you must replace during the race. Your body tolerates a temporary deficit over a 60-120 minute effort; you replace most of it afterwards with food and fluids. The goal during the race is to avoid big swings, not to match losses milligram for milligram.
Before the race
The ACSM stand suggests drinking about 5-7 mL per kg of body weight at least 4 hours before exercise (about 375-525 mL for a 75 kg athlete), and more a couple of hours out if you're not passing urine or it's dark. It notes that salty snacks or a sodium-containing drink help you retain that fluid.
A practical pre-race routine:
- Normal, salted meal 3-4 hours before.
- 400-600 mL of fluid with that meal, or with an electrolyte drink if you're a salty sweater.
- Small sips in the last hour. Don't chug.
During the race
Hyrox runs 8 x 1 km runs, each followed by a station (SkiErg, sled push, sled pull, burpee broad jumps, row, farmers carry, sandbag lunges, wall balls). There's not much room to drink. Check your event's athlete guide for where water is available. If you plan to take sodium on course, practise it in training first: gels, salt tabs or a drink you know your stomach handles at race effort.
The real risk: drinking too much
Drinking far beyond your sweat losses, especially plain water, can dilute blood sodium (hyponatremia). The ACSM stand warns against drinking more than you sweat. For a race this length, overdrinking is more common than serious sodium depletion. Drink to plan or to thirst, not "as much as possible".
Who should be careful
If you have high blood pressure, kidney or heart conditions, or are on a sodium-restricted diet, don't follow general sodium advice. Ask your doctor. This page is general information, not medical or coaching advice.
Tools
- Pace your race: our free Hyrox split calculator builds a run, Roxzone and station pace card from your target time.
- Training from zero: Free Hyrox training plan for beginners.
- Racing HYROX Anaheim (December 3–6, 2026)? Race-morning sodium + creatine timeline for Anaheim.
- Racing HYROX Nashville (December 9–13, 2026)? Race-morning sodium + creatine timeline for Nashville.
- If you want sodium and creatine in one daily scoop, DO IT Creatine Hydration has 1,000 mg sodium, 200 mg potassium, 60 mg magnesium and 5 g creatine per serving, no caffeine. It's a daily drink, not a race-day requirement; salted food, LMNT, Precision Fuel & Hydration or any sodium drink you tolerate work too. Is a combined drink worth it? Read the honest breakdown.
FAQ
How much sodium do I need during Hyrox?
For most people racing 60-120 minutes in a normal venue, little or none during the race if they start hydrated. Salty sweaters or hot venues may benefit from a few hundred mg before and during.
How much sodium do you lose in Hyrox?
It depends on sweat rate and sweat saltiness. A typical athlete losing 1-2 L of sweat at an average concentration loses roughly 800-1,600 mg; salty sweaters can lose twice that.
Should I drink electrolytes before Hyrox?
If you're a heavy or salty sweater, a sodium drink or salty snack with your pre-race fluid helps you retain it (ACSM, 2007). Otherwise a normal salted meal is enough.
Can I drink too much water before or during Hyrox?
Yes. Drinking well beyond sweat losses can cause low blood sodium. Drink to a plan or to thirst.
Do I need salt tablets for Hyrox?
Usually not. Consider them only if you know you're a salty sweater, and test them in training first.
Sources
- American College of Sports Medicine; Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. Exercise and fluid replacement. Med Sci Sports Exerc. 2007;39(2):377-390. https://doi.org/10.1249/mss.0b013e31802ca597
- Thomas DT, Erdman KA, Burke LM. Nutrition and athletic performance (ACSM, Academy of Nutrition and Dietetics, Dietitians of Canada joint position). Med Sci Sports Exerc. 2016;48(3):543-568. https://doi.org/10.1249/MSS.0000000000000852
Unofficial guide. Not affiliated with, endorsed by or connected to HYROX. DO IT is a free workout app that also sells a creatine and electrolyte powder; you don't need it to follow this page.