Sport / Ultra-running

Electrolytes For Ultra-Running

A 50km, 100km or 100-mile trail effort runs six hours or more, often through heat, and the sodium math changes once you pass the marathon mark. LYTES stocks Sodii from $29.95 (Australian-made, 1000 mg sodium per serve) and LMNT from $28.95 (1000 mg sodium per stick) for exactly that distance, with free metro shipping on orders over $149 and dispatch from Wollongong in 12–48 hours.

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What goes wrong on ultra distance

  • Salt crust that shows up after hour four

    White rings on your visor, pack straps and race vest usually appear well past the marathon mark, once hours of sweat have evaporated and left sodium behind. In ultra-distance research, this "salty sweater" pattern is real and measurable, not anecdotal — about one in five distance runners tested lose sodium at more than double the average rate.

  • A vest full of water and nothing else

    Refilling soft flasks with plain water at every aid station tops up fluid but not sodium, so blood sodium gets diluted the longer the race runs. Over 6+ hours that shows up as sloshing, needing more toilet stops, and feeling worse the more you drink.

  • Aid-station guesswork instead of a plan

    Grabbing whatever salt is on the table — chips, pretzels, flat cola — gives you an inconsistent, unmeasured dose exactly when a long race most rewards consistency. A pre-dosed capsule or stick means you know what you took and when, aid station to aid station.

  • Sodium debt that compounds late in the race

    Sodium lost in hour one is small; sodium lost by hour eight is not, because it stacks. Cramping late in an ultra is a well-documented signal of high accumulated sodium loss over a long effort, which is why replacement strategy matters more the longer the race gets — not just in the final hour.

Sweat and sodium on a 6-hour ultra effort

Modelled on published sweat-rate and sweat-sodium research in distance and ultra-endurance runners. Pick your conditions to see roughly what a 6-hour trail effort costs you, and what it takes to put back.

Sweat rate1.0 litres per hour
Sodium in sweat990 mg per litre
Fluid lost over 6 hours6.0 litres

8 × 750 ml bidons

Sweat rate and sweat sodium vary widely between individual runners — treat these figures as a starting point, not a prescription.

Sodium lost in 6 hours 5,940 milligrams

Roughly 5.9 serves of a 1000 mg sodium electrolyte serve, or about 990 mg per hour on the trail.

Plain water replaces none of it.

Sweat rate and sweat sodium figures are drawn from published sports-science research on distance and ultra-endurance runners: Lara et al. (2016), Journal of the International Society of Sports Nutrition, measured sweat sodium concentrations of 7.0–95.5 mmol/L (mean 42.9 mmol/L, ≈990 mg/L) in marathon runners, with about 20% of runners classified as "salty sweaters" above 60 mmol/L (≈1400 mg/L) — doi.org/10.1186/s12970-016-0141-z. Barnes et al. (2019), Journal of Sports Sciences, reported an average endurance-sport sweat rate of 1.28 L/hour and sweat sodium loss of roughly 51.7 mmol (≈1,190 mg) per hour across pooled athlete data — tandfonline.com/doi/full/10.1080/02640414.2019.1633159. Costa et al. (2013), Nutrition Journal, documented ultra-endurance runners across a 225 km, five-day multi-stage race in 32–40°C heat — pmc.ncbi.nlm.nih.gov/articles/PMC3554439. For general context, the American College of Sports Medicine's position stand on exercise and fluid replacement recommends 300–600 mg sodium per hour for exercise lasting over an hour; ultra-specific data shows many ultra runners, especially salty sweaters in heat, sit well above that range over a 6+ hour day. Sweat rate and sweat sodium vary widely between individual runners — treat these figures as a starting point, not a prescription.

Brand in focus

Sodii

1000mg sodium. Australian salt. Zero sugar.

Australian-made with a slightly higher potassium and magnesium count — the default pick for most ultra training and racing.

  • 1000mg sodium per serve - matches LMNT, the highest we stock
  • Made in Australia with Australian salt
  • Zero sugar, naturally sweetened with stevia
  • Free metro shipping over $149
  • Dispatched same day before 12pm AEST
Shop all Sodii

Brand in focus

LMNT

Zero sugar. 1000 mg sodium. Built for people who sweat.

Stevia-sweetened sticks that pack flat in a vest pocket — reach for these when you know you're a salty sweater or racing in the heat.

  • 1000 mg sodium per stick
  • Zero sugar, fasting friendly
  • Free metro shipping over $149
Shop all LMNT

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On the trail the format matters as much as the formula. Pick what suits your vest, your pockets and your drop bags.

Don't forget the other half of fuelling

Electrolytes replace what you sweat out. Carbs replace what you burn.

Past about 90 minutes of trail running, sodium alone will not stop you fading. Gels and chews top up the carbohydrate your legs and lungs are burning, so you can dose salt and fuel separately instead of relying on a single mix to do both jobs.

Shop energy gels & chews

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Three quick questions, one recommendation

Answer three questions about how you run and we'll point you at a brand to start with. Prefer the full version? Take the complete quiz.

How salty do you sweat?

What Australian buyers say

Real reviews from verified LYTES orders across this range.

4.8 from 1,396 reviews
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4 stars 4%
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Collected from verified orders by Judge.me

words can't express how much more active, calm & relaxed I've become since I was put onto this product. Extremely happy 👍🏼

Rob · Verified buyerLMNT Big Fruity Pack - 30 Sticks

Excellent product from an excellent online retailer

I'm happy to be buying my LMNT electrolytes from LYTES. My subscription is easy to manage and adjust as my needs change. I appreciate the free shipping on my large orders.

K.C. · Verified buyerLMNT Lemonade Salt Electrolyte Mix - 30 Sticks

Ultra-running and electrolytes, answered

How much sodium should I take per hour during an ultra?

Most distance and ultra-endurance research puts sodium needs at roughly 300-600 mg per hour as a general starting range, with salty sweaters and hot-weather days running well above that. Six-plus hours of racing means the total adds up fast, so plan a per-hour dose rather than reacting late in the race.

What is a "salty sweater" and how do I know if I am one?

It's the sports-science term for someone who loses sodium in sweat at a well-above-average rate — in one study of marathon runners, about one in five sat above 60 mmol/L (roughly 1400 mg/L) of sweat sodium. Visible white salt crust on your hat, pack straps or face after a long run is a common sign, and it's a reason to test a higher-sodium option like LMNT or Sodii rather than guess.

Is LMNT or Sodii better for a 100-miler?

Both carry 1000 mg sodium per serve, so the choice usually comes down to format and taste rather than dose. Sodii is made in Australia with Australian salt and a slightly higher potassium and magnesium count; LMNT is stevia-sweetened sticks that pack flat in a vest pocket. Many ultra runners carry both and rotate across a long day.

Do I need electrolytes for training runs, or just race day?

For anything under about 90 minutes in mild conditions, water and a normal diet usually cover it. Once training runs stretch past that, especially back-to-back long days building toward an ultra, replacing sodium the same way you plan to on race day is worth practising — race day is the wrong time to test a new product or dose.

Capsules or a drink mix for an ultra?

Capsules keep your bottles neutral so you can dose salt by the hour and fuel separately with gels or real food, which suits hot, long days. A drink mix gets fluid and sodium in together in one hit, which some runners find simpler to remember when they're tired late in a race. Plenty of runners use a mix early and switch to capsules once their stomach gets fussy.

How fast will my order arrive before race day?

We dispatch from Wollongong within 12 to 48 hours, and most customers see next-day delivery including regional addresses — order with a buffer if you're travelling to a race. Free metro shipping applies on orders over $149, and unopened, unused items can be returned within 30 days.

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