Sport / Triathlon

Electrolytes For Triathlon

The swim doesn't cost you sodium — the bike and the run do, back to back, with no break to reset. This page covers what a sprint to full-distance day actually costs you in sodium, and which LYTES formats fit a bento box, a special needs bag or a pocket with no bottle in it. Redmond Re-Lyte tubs run $1.00–1.25 a serve and LMNT sticks carry 1000 mg sodium each, both dispatched from Wollongong in 12–48 hours with free metro shipping over $149.

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What goes wrong on race day

  • Legs give out on the run, not the bike

    The run leg is where sodium debt from the swim-to-bike transition catches up with you. Heavy legs and slowing pace in the final kilometres are a signal of hours of sodium loss that a start-line bottle never covered.

  • A wetsuit swim hides how hot you already are

    Neoprene traps heat before you've pedalled a metre, so you can exit the water already running warm even though the swim itself barely made you sweat. Riders who skip sodium until T2 are starting the two hardest legs already behind.

  • Aid-station cups are built for carbs, not sodium

    Course drink stations are dosed for fuelling, not sodium replacement — thin on salt and heavy on sugar. Relying on them alone means your electrolyte intake is whatever the race organiser decided, not what your sweat rate needs.

  • One plan for three sports is asking too much of a single bottle

    Swim, bike and run have completely different sweat rates and completely different ways of carrying anything. A single race-morning bottle mix cannot flex across all three, which is why the format matters as much as the dose.

Sweat and sodium across a triathlon

Figures for a competitive age-grouper racing Olympic distance (1500 m swim, 40 km bike, 10 km run) in roughly 2.5 hours. The swim leg — around 20–25 minutes of that time, submerged and wetsuit-cooled — contributes negligible sweat loss, so almost all of it is generated on the bike and the run. Pick the conditions to see what that costs and what it takes to replace.

Sweat rate0.9 litres per hour
Sodium in sweat950 mg per litre
Fluid lost over 2.5 hours2.3 litres

3 × 750 ml bidons

Sweat rate and sweat sodium vary widely between triathletes, and running sweats you at a higher rate than cycling at the same effort. Use these as a starting point, not a prescription.

Sodium lost over 2.5 hours 2,138 milligrams

Roughly 2.1 serves of a 1000 mg sodium electrolyte serve, or about 855 mg per hour across the race.

Plain water replaces none of it.

Sweat rate and sweat sodium ranges are typical figures for Olympic-distance triathlon, not a measurement of any individual athlete. The bike/run split is grounded in Speedy DB, Rogers IR, Noakes TD, et al., "Fluid Balance During and After an Ironman Triathlon," Clinical Journal of Sport Medicine (2001), which recorded median fluid losses of 808 mL/hr on the bike and 1,021 mL/hr on the run in Ironman-distance racing — the closest published sweat data broken out by discipline, and the reason our warm-conditions blended rate (0.9 L/hr) sits between those two figures. Sweat sodium concentration (average ~950 mg/L, range roughly 200–2,300 mg/L) is drawn from Precision Fuel & Hydration's sweat-testing data. Sweat rate examples for hot vs cool conditions on the run (0.5 L/hr cool to 1.5–2 L/hr hot) are drawn from USA Triathlon's guide to sweat rate and hydration. For general context, the American College of Sports Medicine's position stand on exercise and fluid replacement puts sodium needs for exercise over an hour at 300–600 mg/hour — our mild-conditions figure (≈420 mg/hr) sits inside that range, and warm/hot conditions push above it, consistent with triathlon's longer combined bike+run exposure. Use this as a starting point, not a prescription — see a sports dietitian for individual advice.

Brand in focus

Redmond Re-Lyte

810mg sodium. Real salt from an ancient seabed. Zero sugar.

The best-value tub in our range, and the one triathletes reach for to cover training volume between races.

  • 810-1000 mg sodium per serve, from Redmond Real Salt
  • Zero sugar, naturally sweetened with stevia
  • $1.00-$1.25 a serve in the tub - our best-value tub format
  • Free metro shipping over $149
  • Dispatched same day before 12pm AEST
Shop all Re-Lyte

Brand in focus

LMNT

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

The higher, more concentrated sodium dose we stock, built for hot race days and the heaviest sweaters.

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

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Race day the format matters as much as the formula. Pick what suits your bento box, special needs bag or T2 bucket.

Don't forget the other half of fuelling

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

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

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Three quick questions, one recommendation

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

How salty do you sweat?

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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

Triathlon and electrolytes, answered

Do I need electrolytes during the swim leg?

Usually not. You're submerged and typically wetsuit-cooled, so the swim itself generates very little sweat compared to the bike and run. Most triathletes save their sodium plan for T1 onward.

How much sodium should I take per hour across the bike and run?

Based on the ranges above, a competitive age-grouper is typically losing somewhere between 400 and 1,500 mg of sodium per hour across the two legs combined, scaling with heat and how salty a sweater you are. Start in the middle of that range and adjust based on conditions and how you feel late in the run.

Should I mix electrolytes into my bike bottle or take them separately?

Both work. Mixing into your bottle gets fluid and sodium in together, which is simple to remember. Capsules or chews let you keep your bottle for plain water or carbs and dose sodium on its own schedule — useful if you're already running a carb-heavy fuelling plan on the bike.

Redmond Re-Lyte or LMNT for triathlon — how do I choose?

Both are zero sugar. Re-Lyte sits at 810 mg sodium (flavoured) to 1000 mg (Unflavoured) per 5 g serve with real Redmond salt, potassium, magnesium and calcium, and its tub is the best-value format for training volume. LMNT is 1000 mg sodium per stick with no sugar — the higher, more concentrated dose, which suits salty sweaters and hot race days. Many triathletes train on Re-Lyte tubs and race with LMNT sticks for the convenience.

Does the plan change between sprint, Olympic and full distance?

Yes — mainly on duration. A sprint or Olympic day may only need sodium from T1 onward, similar to the ranges above. A half or full distance day extends that same per-hour rate over many more hours, which is why format matters more at longer distance: you need something you can carry and dose without a support crew.

How fast will my order arrive, and what if I don't like what I ordered?

We dispatch from Wollongong within 12 to 48 hours, and free metro shipping kicks in over $149. Unopened, unused items in their original packaging can be returned within 30 days.

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