Quick answer: sodium and potassium are the two electrolytes that do most of the work when it comes to hydration. Sodium is the main electrolyte you lose in sweat and it helps your body hold on to the fluid you drink. Potassium works alongside it, mostly inside your cells. You don't need to calculate a perfect ratio. For most people, a balanced diet, regular water and an electrolyte drink after sweaty sessions or hot days keeps things on track.
Sodium and potassium come up a lot in conversations about hydration, sweat tests and electrolyte drinks. They also get confusing quickly, with numbers, ratios and plenty of mixed messages online. This guide keeps it simple: what each one does, why they're usually talked about as a pair, where you get them from, and how to read the label on an electrolyte drink.
What are electrolytes, in plain English?
Electrolytes are minerals that carry a small electrical charge when they're dissolved in water. Your body uses them to manage where fluid goes and to help your muscles and nerves do their everyday jobs. The main ones are sodium, potassium, chloride, magnesium and calcium.
When you sweat, you lose water and some of these minerals. That's why the question of what to drink after training or a long day in the sun is about more than just water. If you're still deciding whether you need electrolytes at all, start with our guide to electrolytes vs water.
Sodium: the one you lose most in sweat
Sodium is the electrolyte found in the highest amounts in sweat. It's also the one that helps your body hang on to the fluid you drink, rather than passing straight through. That's why sports scientists and dietitians tend to focus on sodium first when they talk about rehydrating after heavy sweating.
Everyone sweats differently. Some people finish a session with white, salty marks on their hat or shirt. Others barely leave a trace. If you're a salty sweater, training in the heat, or working long outdoor shifts, sodium is the part of your hydration to think about. Our article on sodium and sweat goes deeper, and sweat tests explains how athletes measure their own losses.
Potassium: the partner that works inside your cells
Potassium is the other half of the pair. Where sodium is found mostly in the fluid around your cells, potassium is found mostly inside them. Together they help your body balance fluid between the two.
You lose some potassium in sweat, but much less than sodium. The good news is that potassium is easy to get from everyday food. Bananas, potatoes, avocado, leafy greens, beans, yoghurt and plenty of fruit and vegetables all contribute.
Why sodium and potassium are talked about together
Sodium and potassium are a team. Your body is constantly moving them across cell walls to manage fluid and keep muscles and nerves firing as normal. That's why you'll often see them listed side by side on the back of an electrolyte drink.
A few simple points help cut through the noise:
- There's no magic ratio for everyday drinking. Different drinks use different amounts, and your food does a lot of the work.
- Sweat losses are mostly sodium. After heavy sweating, sodium is the one to prioritise.
- Food covers most potassium needs. A drink adds a little on top.
- More isn't always better. Very high doses aren't needed for a gym class or a warm afternoon.
Where do you get sodium and potassium?
| Electrolyte | Main job | Everyday sources |
|---|---|---|
| Sodium | Helps your body hold on to fluid; main electrolyte lost in sweat | Salt, bread, cheese, savoury meals, electrolyte drinks |
| Potassium | Works inside your cells to balance fluid with sodium | Bananas, potatoes, avocado, greens, beans, yoghurt, fruit |
When does the balance matter most?
For most people on most days, regular meals and water are plenty. Sodium and potassium become more worth thinking about when you lose more fluid than usual:
- Long or sweaty training sessions, like HYROX, long runs, hot Pilates or summer footy. See our pre and post training hydration guide.
- Hot Aussie days and heatwaves. Our hot weather hydration guide has simple tips.
- Long shifts and outdoor work, from tradies on site to nurses and emergency crews. Read hydration for shift workers.
- Sauna, ice baths and contrast therapy, where you can sweat more than you realise.
How to read the label on an electrolyte drink
- Check the sodium. If you want a drink for sweaty sessions, sodium should be a meaningful amount, not a token sprinkle.
- Look for potassium too. A drink with both sodium and potassium covers the main pair.
- Check where they come from. Real salt and simple mineral sources are easy to understand on a label.
- Watch the sugar. For everyday hydration, low sugar or no added sugar makes sense. Our guide to low sugar sports drinks explains when sugar is actually useful.
- Keep the list short. Fewer, recognisable ingredients beat a long list of additives.
How Uthrive gets sodium and potassium into the can
We keep it simple with two sources. Sodium comes from real salt harvested at Lake Deborah in Western Australia. You can read the full story in Lake Deborah salt in Uthrive. Potassium comes from potassium citrate, which we explain in sodium and potassium, side by side.
Add real fruit, lightly sparkling water, no added sugar and nothing artificial, and that's the drink. Every ingredient is listed in what's in Uthrive.
Real salt. Real fruit. Hydrated by Nature.
Try Passionfruit, Orange or Pineapple, or grab a mixed box of all three.
Frequently asked questions
What's the difference between sodium and potassium?
Both are electrolytes. Sodium is found mostly in the fluid around your cells and is the main one lost in sweat. Potassium is found mostly inside your cells. They work together to balance fluid.
Do I need a specific sodium to potassium ratio?
Not for everyday hydration. A balanced diet, regular water and an electrolyte drink after heavy sweating covers most people. If you have a specific health condition, talk to your doctor.
Which electrolyte matters most after sweating?
Sodium. It's lost in the highest amounts in sweat and helps your body hold on to the fluid you drink.
Can I get enough potassium from food?
For most people, yes. Fruit, vegetables, beans, potatoes and dairy are all good everyday sources.
Which electrolytes are in Uthrive?
Sodium from Lake Deborah salt and potassium from potassium citrate, with real fruit and no added sugar.
General information only, not medical advice. If you have a health condition or take medication that affects sodium or potassium, talk to your doctor about your hydration needs.
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