Hydration for runners can often feel confusing.

You’ve probably seen a lot about electrolytes lately - they’re everywhere - but do you actually need them? And how much should you really be drinking on a run?

The truth is, hydration isn’t one-size-fits-all and women’s needs can vary depending on training load, environment, and even hormonal changes.

In this guide, we’ll break down hydration for running in a simple, practical way — so you can feel confident heading out, whether it’s a short training run or a long day on the trails.

Why hydration is important for runners

Hydration plays a key role in how you feel and perform, especially as your runs get longer.

How much you need depends on:

• your sweat rate
• temperature and humidity
• how hard you’re running
• how long you’re out for

👉 And importantly for women:

• hormonal fluctuations can impact fluid balance
• hydration needs may shift across your cycle

In warmer conditions or higher intensity sessions, you’ll lose more fluid and electrolytes through sweat.

Even mild dehydration matters.

As little as 2% dehydration can:

• reduce concentration
• increase perceived effort
• make running feel harder than it should

Waiting until you feel thirsty isn’t ideal - especially on longer runs or if you start already slightly dehydrated.

How much should you drink?

This is one of the most common questions around hydration for runners - and the answer is - it depends.

As a general guide:

• 400–800ml of fluid per hour works well for most women
• adjust based on body size, sweat rate and conditions

Some women naturally lose more fluid and sodium than others, even in similar conditions.

Signs you may be a heavier or saltier sweater:

• sweat stinging your eyes
• salty taste on your skin
• white salt marks on clothing

👉 The key is to practise your hydration strategy during training - not waiting until race day.

Do female runners need electrolytes?

For shorter runs (under 60 minutes at an easy pace), water is usually enough.

You’ll likely get sufficient sodium from your daily diet.

But for:

• runs longer than 60–90 minutes
• higher intensity sessions
• hot or humid conditions

👉 electrolytes become important

What are electrolytes and why do they matter?

Electrolytes are minerals that help regulate:

• fluid balance
• muscle contraction
• nerve signalling

The most important one for runners is sodium.

When you sweat, you lose sodium - not just water.

If you only replace fluids without sodium, you may start to feel:

• fatigued
• dizzy
• bloated
• mentally foggy

In more extreme cases, drinking large amounts of water without sodium during long runs can lead to hyponatraemia(low blood sodium levels).

How many electrolytes do you need?

There’s no one-size-fits-all approach, but a good starting point is:

• 500mg sodium per litre of fluid

From there, adjust based on:

• how much you sweat
• conditions
• how you feel during and after runs

Hydration for long runs and ultra training

For longer runs, hydration becomes less about guessing and more about having a plan.

For shorter sessions, you might:

• carry a small handheld bottle
• tuck a gel or sweets into your shorts pocket

For longer runs, having the right setup makes everything easier.

👉 A women’s-specific hydration vest like the Artemis 5L Race Vest allows you to:

• carry fluids, fuel and electrolytes comfortably
• sip regularly without stopping
• keep everything easily accessible as fatigue builds

Because hydration isn’t just about what you carry — it’s about how easily you can actually use it while running.

Practical hydration tips 

• Start your run well hydrated
• Sip regularly from the beginning
• Avoid drinking large amounts all at once
• Adjust your intake based on effort and conditions
• Check hydration through urine colour (pale straw = well hydrated)
• Practise your hydration strategy in training

For longer runs, it can also help to carry:

• electrolyte tablets
• extra fuel
• slightly more fluid than you think you’ll need

Final thoughts on hydration 

Hydration doesn’t need to be complicated.

It just needs to be:

• consistent
• practised
• personalised

What works for someone else might not work for you and that’s completely normal.

The goal is to feel strong, comfortable and confident in your approach, so you can focus on the miles ahead.

FAQs: Hydration for female runners

How much water should you drink per hour?
Most women runners need between 400–800ml per hour depending on conditions, body size and sweat rate.

Do you need electrolytes?
Electrolytes are helpful for runs longer than 60–90 minutes, especially in warm conditions or during harder efforts.

Can I just drink water on long runs?
For shorter runs, yes. For longer runs, adding electrolytes helps replace sodium lost through sweat.

What next?

This blog is a general guide and doesn’t take into account individual medical conditions or specific dietary needs.

Special thanks to Gemma for her expertise on this blog.

About Gemma

A Registered Sports Dietitian (SENr), Gemma is a keen trail and ultra runner with over eight years’ NHS experience. With a First Class degree in Dietetics and a postgraduate in Sports Nutrition, she combines clinical expertise with lived running experience to help women fuel and perform at their best.

For personalised advice, you can connect with Gemma via Instagram:
@this_dietitian_runs or @ghperformancenutrition