Electrolyte Drink Dosage: How Much Sodium and Fluid You Need

For most endurance sessions longer than an hour, aim for roughly 300 to 600 mg of sodium per hour, mixed at about 700 to 900 mg of sodium per liter of fluid, and keep your total fluid intake under about 700 ml per hour. That is a starting point, not a prescription. Your sweat rate, the heat and the length of your session move the number up or down, and the rest of this guide shows you how to work out your own dose.

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TL;DR

Under 60 minutes, water is usually enough. Past 60 minutes, a drink with sodium and carbohydrate starts to earn its place.
Typical range for prolonged exercise in heat: 300 to 600 mg of sodium per hour, or 700 to 900 mg per liter of fluid.
Pair sodium with 30 to 60 g of carbohydrate per hour, and do not drink more than about 700 ml per hour.
On rest days you do not need an electrolyte drink. Drink to pale urine.
Test your dose in training, then adjust with a sweat test or simple before-and-after weigh-ins.

When Water Is Enough and When It Is Not
The Core Numbers: Sodium Per Hour and Per Liter
How Much Fluid Goes With It
Add Carbohydrate to the Equation
Adjusting for Singapore Heat, Sweat Rate and Duration
Capsules, Chews and Powders: Same Dose, Different Format
High-Intensity Days and HYROX
Perspective
Build Your Hydration Kit
Practical Tips Before You Test Your Dose
FAQ
Sources

When Water Is Enough and When It Is Not

Electrolyte drink dosage only matters once the session is long enough to need it. Sport Singapore advises isotonic or sports drinks for any activity lasting more than an hour. The ACSM position stand adds that for exercise under one hour there is little evidence of a performance difference between a carbohydrate-electrolyte drink and plain water.

So a 45-minute easy jog around MacRitchie does not need a mixed bottle. A 90-minute long run, a two-hour ride or a full HYROX race day does. Our guide to why electrolytes matter for running explains what sodium, potassium, magnesium and calcium each do. For the full definition, see electrolytes explained for athletes.

The Core Numbers: Sodium Per Hour and Per Liter

There are two ways to read dosage, and both point to the same range.

Per hour. A 2022 review of sodium intake in sport reports general recommendations of 300 to 600 mg of sodium per hour during prolonged exercise. It also says individual needs vary a lot with sweat rate and sweat sodium concentration. The same paper gives that 300 to 600 mg range for hot (above 25°C) and humid (above 60%) conditions.

Per liter. Runner’s World UK suggests 700 to 900 mg of sodium per liter of fluid, which works out to about 350 mg in a 500 ml bottle. The ACSM recommends 0.5 to 0.7 grams of sodium per liter during exercise longer than an hour. It notes this may improve palatability, help fluid retention and possibly help prevent hyponatremia in people who drink excessive amounts.

Sodium concentration ranges per liter compared

Worked example: from label to bottle

Say your drink mix lists 400 mg of sodium per serving, and the label says to mix one serving into 500 ml.

Concentration: 400 mg in 0.5 L equals 800 mg per liter. That sits inside the 700 to 900 mg range.
Hourly intake: if you drink one 500 ml bottle per hour, you take in 400 mg of sodium per hour. That is inside the 300 to 600 mg range.
If you drink 700 ml per hour of the same mix, you take in 560 mg per hour. Still in range.

The maths is simple, but it only works if you read the serving size. A product listing 500 mg of sodium per serving is not stronger than one listing 300 mg if the first is mixed into a liter and the second into 300 ml.

Fluid per hour	Mix at 700 mg/L	Mix at 900 mg/L
400 ml	280 mg	360 mg
500 ml	350 mg	450 mg
600 ml	420 mg	540 mg
700 ml	490 mg	630 mg

The table is arithmetic on the per-liter range above. If you sit near the top of the fluid column, choose the lower concentration so your hourly sodium stays near the 300 to 600 mg guideline.

How Much Fluid Goes With It

Sodium dosage is meaningless without a fluid target. Sport Singapore recommends drinking 250 to 500 ml every half hour during exercise to avoid dehydration or overheating, and ideally about 500 ml of water 30 minutes before you start. For a pre-run routine, this Hyrox hydration plan walks through how to start a session well hydrated.

There is also a ceiling. Armstrong (2021) recommends keeping fluid intake below 700 ml per hour to lower the risk of exercise-associated hyponatremia. The same review says weight gain during endurance exercise should be avoided, because it typically signals fluid retention and a higher risk of that condition. Drinking more is not safer. Drinking to a plan is.

How Much Fluid Goes With It

Before you start

A 2025 review on sodium for athletes notes that acute sodium loading of about 275 to 420 mg per 100 ml of fluid can improve fluid retention before exercise. Try this only in training and only if you are prone to finishing sessions badly dehydrated. Do not first experiment with it on race morning.

Add Carbohydrate to the Equation

If the drink is your fuel as well as your hydration, carbohydrate belongs in the dose. Coyle (2004) reports that 30 to 60 grams of rapidly absorbed carbohydrate per hour can reduce fatigue. The ACSM recommends the same 30 to 60 g per hour for intense exercise longer than an hour, in a 4% to 8% carbohydrate solution.

A 6% solution is 60 g per liter, so 500 ml gives you 30 g. If you drink 500 to 700 ml per hour of a 6% mix, you cover the lower half of the carbohydrate range from the bottle alone. Many athletes then add a gel to reach their target. Browse our energy gels and hydration range to build that stack, or read the types of sports drinks comparison to see how isotonic, hypotonic and hypertonic drinks differ.

Adjusting for Singapore Heat, Sweat Rate and Duration

Published ranges are averages. The research is clear that intake should be adjusted for environment, individual sweat rate and exercise duration. Coyle (2004) says sodium should be included in fluids for exercise longer than two hours, or for people with heavy sodium losses (more than 3 to 4 g). The NATA position statement recommends individualizing sodium before and during exercise based on specific losses and needs.

Here is how that looks in practice:

60 to 90 minutes, warm morning: a drink at the lower end, around 300 to 400 mg of sodium per hour, and fluid by thirst within the limits above.
Two hours or more in midday heat: work toward the middle or upper part of the 300 to 600 mg range, and add carbohydrate.
Visible salt crust on your kit or stinging eyes: you may be a salty sweater. Move to a sweat test rather than guessing.
Cool, short, easy session: water is fine.

Singapore training often means warm, humid conditions, which is the situation the 300 to 600 mg guidance is written for. If you are racing a marathon, our electrolyte balance during a marathon guide breaks the plan down by race stage.

Find your personal number

Runner’s World UK points out that a sweat test is the easiest way to learn your own sodium losses and move past rules of thumb. Without one, a simple method works:

Weigh yourself nude before and after a one-hour training run, noting what you drank.
Weight lost plus fluid drunk gives a rough sweat volume for that hour.
Aim to finish near your starting weight, never above it.
Repeat in different conditions and write the results down.

The 2025 review above recommends monitoring body weight changes to estimate fluid loss and avoiding over-drinking. If you gain weight during a long session, you drank more than you lost, so cut back.

Capsules, Chews and Powders: Same Dose, Different Format

You do not have to take all your sodium from a bottle. Some runners dislike salty drinks, or race with a handheld flask of plain water. In that case you can split the dose: a capsule or chew provides the sodium, and the flask provides the fluid.

SaltStick Electrolyte Caps suit long sessions where you want to adjust the dose in small steps.
SaltStick FastChews are quick to take on the move when you do not want to unscrew anything.
Electrolyte powders let you mix to a target concentration. Our best electrolyte powder guide helps you pick one for your situation.

Whichever format you choose, add up the sodium from every source in the hour. A bottle at 400 mg plus two capsules on top can push you well past the 600 mg guideline without you noticing. For the safety limits on powders, read when to use electrolyte powders.

High-Intensity Days and HYROX

A HYROX race mixes running with sled pushes and wall balls, so you sweat hard but cannot carry much. Short breaks between stations are your drinking windows. Plan small sips each time rather than waiting for a big drink, and keep the total within the hourly limits above. Our article on electrolytes in high-intensity training covers why the demands differ from steady running.

Perspective

We see the same mistake every race season: athletes copy a number from a friend, then wonder why they cramp or feel bloated at kilometer 30. Dosage is a personal setting, not a universal one.

Our approach is to start from the published ranges, test them in training, and change only one thing at a time. That is why we stock sodium in several formats, from drink mixes to capsules and chews, so you can build the plan that suits your stomach, your sweat and your race.

We are an official retailer for the brands we carry, and we aim to make trusted products easy to get with next-day delivery in Singapore. Your job is to turn up to training with a plan. Ours is to make sure the product in your bottle is the one on the label.

Jason John

Build Your Hydration Kit

Once you know your target, stock up before your next long run. We carry electrolyte capsules and chews, energy gels, hydration drinks and recovery formulas from leading international brands, all shipped next-day within Singapore.

Start with the Racepack.sg hydration and energy range, or browse recovery powders for after your session.

Practical Tips Before You Test Your Dose

Read serving size first, then calculate sodium per liter.
Test new mixes on training days, never on race day.
Start at the lower end and move up only if you finish sessions with salt crust, cramps or heavy fatigue.
Sip regularly rather than gulping at aid stations.
Keep a log: duration, temperature, fluid, sodium, carbohydrate, and how you felt.
See a doctor or sports dietitian before changing sodium intake if you have high blood pressure, kidney or heart conditions, or take medication that affects fluid balance.

FAQ

How much electrolyte drink should I have per hour when running?

Most guidance points to 300 to 600 mg of sodium per hour in hot, humid conditions. In bottle terms, that is roughly 500 to 700 ml of a drink with 700 to 900 mg of sodium per liter. Start lower and adjust based on how you feel and how much weight you lose.

How much sodium per liter should an electrolyte drink contain?

A common starting point is 700 to 900 mg of sodium per liter, or about 350 mg in a 500 ml bottle. The ACSM range of 0.5 to 0.7 g per liter is slightly lower. Choose within that band and refine it with a sweat test.

Do I need an electrolyte drink for a 30 to 45 minute workout?

Usually not. Evidence shows little performance difference between a carbohydrate-electrolyte drink and water for sessions under an hour. Drink water and eat a normal meal afterward.

Can I drink too much fluid during exercise?

Yes. Excessive fluid can cause exercise-associated hyponatremia, where blood sodium falls too low. Research suggests keeping intake below about 700 ml per hour and avoiding weight gain during long efforts. If you feel nauseated, bloated or confused, stop and seek medical help.

Do I need carbohydrate in my electrolyte drink?

For intense exercise longer than an hour, 30 to 60 g of carbohydrate per hour is recommended, in a 4% to 8% solution. A sugar-free electrolyte mix is fine if you take carbohydrate from gels or chews. Add up all sources so you hit your hourly target.

Should I take electrolyte drinks on rest days?

No evidence shows that athletes need more dietary sodium day to day, and supplementing is unnecessary when you are not significantly dehydrated. A general rule from HealthHub is to drink enough that your urine is pale. If you have a medical condition, ask your doctor first.

How do I know if I am a salty sweater?

White salt marks on kit, stinging eyes and a strong taste on your lips are common hints. A sweat test gives a real number. Heavy sodium loss is described as more than 3 to 4 g, and such athletes benefit most from sodium in fluids during long sessions.

Should I use capsules, chews or a drink mix?

All can deliver the same sodium dose. A drink mix gives fluid and sodium together, while capsules and chews let you separate them and fine-tune. Many athletes use a mix for the base dose and a chew or capsule for extra salty sweat days.

Where can I buy sports electrolytes in Singapore with next-day delivery?

You can shop electrolyte capsules, chews, hydration drinks and energy gels at Racepack.sg, with next-day delivery within Singapore. We sell from international brands as an official retailer.

Ready to dial in your plan? Buy Now at Racepack.sg and get your hydration kit delivered next day.