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Electrolytes Explained: The Key to Hydrating Well!
Electrolytes explained, how much do you sweat? And your next best training method?
Matthew Sharpe
September 26, 2025
TOGETHER WITH PRECISION FUEL & HYDRATION
Good morning everyone,
I’m just finishing up today’s edition while watching the World Triathlon Series race in China. And I’m getting a flood of memories from my time chasing the series around the world, including my eight-race in eight-weekend racing odyssey.
Starting in Australia, I bumped around to the US, Jersey (U.K.), Ecuador, Malta, and Spain. I probably should have called it after three races or so, but three races doesn’t exactly sound like much of an odyssey!
In today’s edition:
🧂 Electrolytes explained: The key to hydrating well!
🥵 How much do you actually sweat?
🏃 And your next best training method?
-Matt Sharpe, newsletter editor
Have a triathlete in your life who can't stop swimming, biking, or running? Fire this off to them. Forwarded from a friend? Sign-up for free.
TRAINING THOUGHT
Electrolytes Explained: The Key to Hydrating Well!
IRONMAN
For triathletes, electrolytes aren’t just a few extra shakes of the salt at dinner; they're the difference between a breakthrough race and a bust!
But why do they matter to you? And which ones will help you stay hydrated and on top of your game? Find out below!
What Are Electrolytes, Really?
Electrolytes are literally electric! They carry a charge and are responsible for maintaining fluid balance, conducting nerve impulses, and contracting muscles. You lose these crucial minerals through sweat, which is why plain water just isn’t going to cut it!
🧂 Sodium
It’s the star player in fluid retention and absorption, and helps your body retain water and enables rapid hydration by enhancing water uptake in your intestines.
Why you need it: During intense exercise, you can lose up to 1000mg of sodium through sweat! Low sodium levels lead to muscle cramps, fatigue, and in extreme cases, dangerous hyponatremia.
🍌 Potassium
Potassium works in tandem with sodium to regulate fluid balance, but its true superpower lies in supporting muscle and nerve function. It’s essential for proper muscle contractions and preventing cramping.
Why you need it: Although you don’t lose as much potassium through sweat as sodium, deficiency can cause muscle weakness, cramping, and irregular heartbeats.
Look for 80-200 mg per serving in your sports drink, with higher amounts for longer training sessions or if you’re a heavy sweater.
🌿 Magnesium
Magnesium is a part of over 300 enzymatic reactions in your body. It supports muscle and nerve function, helps control blood sugar, and assists in protein synthesis and recovery.
Why you need it: Intense training increases magnesium needs, and deficiency is linked to muscle cramps, fatigue, and poor recovery. Plus, many athletes are already running a magnesium deficit in their diet.
And it can also serve as a great daily supplement to support a multitude of processes in your body.
🥛 Calcium
While famous for bone health, calcium is crucial for muscle contractions, including your heart muscle! It also plays a role in nerve transmission and blood clotting.
Why you need it: Calcium deficiency can lead to muscle cramps and impaired muscle function. During long training sessions, maintaining adequate calcium levels supports performance.
🌊 Chloride
Chloride works primarily with sodium to maintain fluid balance and is a significant component of stomach acid, supporting digestion.
Why you need it: You lose chloride along with sodium when you sweat. It’s essential for maintaining proper hydration and preventing the muscle cramps associated with electrolyte imbalance.
If you can, look for products that use either sodium chloride for a more direct replacement of sweat losses or sodium citrate for easier digestion and better taste.
The Science of Absorption
The magic happens when these electrolytes work together. Like when sodium and glucose create a transport system in your intestines that accelerates water absorption.
This is why sports drinks are more effective for rapid hydration than plain water!
The ideal ratio matters as well. Excessive intake of any single electrolyte can actually slow absorption or cause gastrointestinal distress. It’s why sports drinks are formulated based on research into sweat composition and absorption rates.
When Do You Actually Need Them?
For workouts under an hour, water can often be enough. But when you’re training for more than 60 minutes, in hot conditions, or if you’re a heavy sweater, electrolyte replacement becomes crucial for maintaining performance and preventing muscle cramps.
For most, sodium in the 400 mg range is adequate, while those very salty sweaters will approach upwards of 1000 mg per hour!
So next time you sip on your bottle, you’ll know exactly what’s working behind the scenes to keep you hydrated, energized, and performing at your best!
TOGETHER WITH PRECISION FUEL & HYDRATION
Do You Know How Much You Actually Sweat?!
Not all sweat is created equal. In fact, sodium loss can vary up to 15× between athletes -and that matters when you’re trying to train and race at your best!
Precision Fuel & Hydration’s Sweat Test is a simple, 45-minute, sit-down session (no treadmill, no blood draw) that reveals exactly how much sodium you lose.
Armed with that data, you get a personalized hydration strategy - what to drink, when, and how much - so you stay strong from the first stroke to the final sprint!
Why you’ll love it:
🏊♂️ Prevent mid-race cramping & fatigue by matching electrolytes to your actual sweat rate.
🚴 Train smarter with a targeted hydration strategy tailored exactly to you!
🏃 Race with confidence knowing your bottle is dialed to your unique needs.
Ready to hydrate like you were meant to?
👉 Book your Sweat Test or start with a free Fuel & Hydration Plan at PrecisionHydration.com.
FAVORITES
🥤 Drink better: Is water what’s best for hydrating? No, according to sports scientist Asker Jeukendrup. Milk, apparently, is best! Water doesn’t even make the top five! Check out this blog on how various drinks stack up against each other for their hydrating properties. [My Sports Science]
📈 Your next best training method? Australia’s Cam Wurf has competed at the highest level of cycling and triathlon at the same time! How did this happen? Non-negotiable training. Find out what this means, and how it can lead to your next best race! [The Tempo]
💆 Recovery with age: Recovering from cycling (and training) as an older athlete can be less predictable at times. This article explains how aging affects cycling recovery, and as it turns out, you can train better recovery! [Trainer Road]
😬 Giant problem: If you’re looking to purchase a Giant bicycle, you may have to wait. US Customs is now detaining all Giant bikes due to allegations of forced labour! [Bicycle Retailer]
TEMPO TALKS PODCAST
Should Athletes Be Punished for Yelling at Officials? Or Encouraged?
And is this the most competitive women’s World Champs ever?!
All this and more in the latest episode of the Tempo Talks Podcast!
Together with The TriDoc, we bring you the biggest stories in Triathlon,
Training tips to make you faster,
And breakdowns of the latest in sports science and performance!
QUICK NEWS
World Champs starters: Charles-Barclay, Philipp, Matthews, Knibb, and so many more. The start list for the Women’s IRONMAN World Championship has been released, and it is exceptional!
Congrats coach: Congrats to Jacob Wolf, who has been named as the Assistant Coach of the Denver Pioneers Triathlon Team! [Denver Pioneers]
Prolific Kiama: Kiama went from being triathlon-less for 10 years to hosting two in the same year! And the next one is the perfect warm-up for the upcoming World Triathlon Wollongong World Champs! [Bugle News]
Vietnamman: As Đà Nẵng prepares to host the first-ever full-distance IRONMAN in Vietnam, the stakes couldn’t be higher! [Vietnam News]
YOU SAID
Here’s what you thought about whether Triathlon entities chase big-money destination deals!
Reader: Oman had a clear goal to get involved with endurance sport….Was THIS the huge money deal that Sam Renouf was talking about when he said that T100 had lost a potential huge sponsor??? Did Ironman outbid/steal it from them????
Reader: We need to carefully consider 'sports washing', which is a growing concern in cycling at the moment (even though technically triathlon started it with Tri Dubai in the early 2000's).
Reader: “These parts of the world have a reputation as unfriendly to women, and this agreement strikes me as not well-aligned with Ironman's claimed goal of increasing female athlete participation, but I'd love to be wrong about that.
Reader: I raced in Abu Dhabi at olympic-distance worlds a couple of years ago, and it was an amazing experience and trip that was very different from what I would have expected. I would have never visited there if not for the triathlon being there.
Reader: As an American woman and athlete I am skeptical of traveling to middle eastern countries were women don’t have as many rights as we do here. Muscat is viewed as more modern but women traveling alone still have to take many precautions when traveling to middle eastern countries. I’d like to hear feedback from other women competing at these events before I decide to do so myself.
Reader: I'm all good with destination races that can be planned around a vacation, but T100 is mostly out of reach due to exotic locations. IM offers the chance to visit places you never would have normally so need to be kept within reach and budget of regular people.
Reader: I am naturally conservative by nature and like to stick to traditional venues and traditional business practices, but I guess businesses need to grow, adapt, and try new things. What is the saying? “If you’re not growing then you’re dying”? I personally don’t have any desire to travel there and I do not see IM training and racing becoming big in a country that doesn’t already have a presence in track and field, marathoning, cycling or swimming. I’m predicting a flop but hoping for success.
Reader: My opinion and thought is they will have a hard time getting qualified finishers to sign up for this destination.
WEEKEND RACES
IRONMAN 70.3 Chattanooga
Sam Long (USA) and Danielle Fauteux (CAN) lead the charge in Chattanooga!
IRONMAN 70.3 Augusta
Sam Appleton (AUS) and Paula Findlay (CAN) are ranked #1 for Augusta.
LATEST EDITIONS
In Nice’s hangover, T100 athletes impress. Plus: Creatine for endurance.
IRONMAN + Oman partnership worth millions. And stop sinking legs!
Stornes shocks with IMWC victory. Plus: Six devastating run mistakes.
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