Cramping, Heavy Sweating & Stomach Issues: What Can Runners Do?

Running can feel straightforward when everything is going well.

Then suddenly your calf tightens, your clothes are completely soaked through, or your stomach decides halfway through a long run that it has had enough.

Cramping, excessive sweating and stomach problems are three issues that can quickly derail a long training session or race.

Unfortunately, there isn't one product or nutrition strategy that will solve all three.

Understanding what may be contributing to the problem is the first step towards developing a hydration and fuelling strategy that works for you.

Why Do Runners Cramp?

Muscle cramp is often immediately blamed on dehydration or a lack of electrolytes.

The reality is more complicated.

Exercise-associated muscle cramps can have several contributing factors, with muscular and neuromuscular fatigue thought to play an important role. Fluid and electrolyte losses may also be relevant for some runners, particularly when large sweat losses are involved.

That means simply taking more salt isn't automatically going to stop you cramping.

If you regularly cramp towards the end of a race or long run, consider the bigger picture.

Possible contributing factors include:

• Running harder or faster than you're conditioned for

• Significant muscular fatigue

• Inadequate preparation for the distance

• Heavy fluid and electrolyte losses

• Hot or humid conditions

• Poor pacing

• Changes in terrain or elevation

For example, if you repeatedly cramp towards the end of a marathon despite drinking and taking electrolytes, muscular fatigue or pacing may be contributing alongside your hydration strategy.

Can Electrolytes Help With Cramping?

Electrolytes can form part of your overall hydration strategy, particularly if you're losing significant amounts of fluid and sodium through sweat.

But they shouldn't be treated as a guaranteed anti-cramp solution.

If you're a heavy or particularly salty sweater, replacing some of the sodium you're losing may be worthwhile during longer sessions.

We've covered this in much more detail in our guide to why sodium is crucial for running performance.

Products such as electrolyte tablets, drink mixes and electrolyte chews can make it easier to incorporate sodium into your hydration strategy.

You can also explore our full range of electrolytes and salt tablets.

The important thing is to combine your hydration strategy with appropriate training and pacing rather than relying on electrolytes alone.

What Does It Mean to Be a Heavy Sweater?

Some runners naturally sweat considerably more than others.

Your sweat rate can also change depending on:

• Temperature

• Humidity

• Exercise intensity

• Fitness and heat acclimatisation

• Clothing

• Body size

• Individual physiology

Two runners completing exactly the same session can therefore have very different hydration requirements.

A runner who loses large amounts of fluid during exercise may need to pay considerably more attention to hydration during a two-hour long run than someone who sweats relatively little.

Signs You May Be a Heavy or Salty Sweater

You may experience relatively high sweat losses if:

• Your clothing becomes completely saturated during training

• Sweat regularly runs into your eyes

• You notice white salt marks on dark clothing

• Salt crystals are visible on your skin after exercise

• You lose a noticeable amount of body weight during longer sessions

• You finish long runs extremely thirsty

None of these signs tells you exactly how much sodium you're losing.

But they can indicate that your hydration requirements deserve more attention.

Should You Try to Replace Everything You Sweat Out?

Not necessarily.

Trying to replace every millilitre of sweat while you're running isn't always practical or necessary.

Instead, the aim is to develop a hydration strategy appropriate for your individual sweat losses, the conditions and the duration of your run.

This is one reason why simply copying another runner's hydration strategy isn't particularly useful.

Someone beside you may be drinking considerably more or less simply because their sweat rate is completely different.

Use your long training sessions to understand approximately how much you're sweating and how much fluid you're comfortable taking on while running.

What About Stomach Problems While Running?

For many runners, gastrointestinal issues can be even more disruptive than tired legs.

Common complaints include:

• Nausea

• Bloating

• Stomach cramps

• A heavy or sloshing feeling

• Excess gas

• An urgent need to use the toilet

There isn't always one obvious cause.

Running places stress on the gastrointestinal system, particularly as intensity and duration increase. Problems can then be influenced by factors such as your food choices, hydration, carbohydrate intake and how accustomed you are to consuming fuel while exercising.

Are Energy Gels Causing Your Stomach Problems?

Sometimes runners immediately blame energy gels when they experience stomach trouble.

But the gel itself isn't necessarily the problem.

You need to look at your entire fuelling strategy.

For example:

You may be consuming too much carbohydrate too quickly.

You may not have practised your intended race-day intake enough during training.

You may be taking a concentrated carbohydrate product differently from how the manufacturer recommends.

You may be eating too close to the start of your run.

Or you may simply tolerate certain formats, ingredients, textures or flavours better than others.

Different runners can respond very differently to the same product.

That's why your long runs should effectively become race-day rehearsals.

Train Your Gut Like You Train Your Legs

Your digestive system can adapt to consuming fuel during exercise.

Rather than suddenly attempting a much higher carbohydrate intake on race day, introduce your intended strategy during training and build your experience with it.

If you're currently comfortable consuming a relatively small amount of carbohydrate during a long run, for example, you can practise your intended race strategy over multiple sessions while monitoring how your stomach responds.

The objective isn't simply to consume as much carbohydrate as possible.

It's to find an intake that provides the fuel you need while remaining comfortable and sustainable.

Repeatedly practising your strategy also gives you an opportunity to test different products and formats before race day.

Don't Introduce New Nutrition on Race Day

Race morning is not the time to discover whether a new gel agrees with your stomach.

Ideally, you should have already practised:

• Your pre-race breakfast

• Your hydration strategy

• Your chosen gels, chews or drink mix

• How frequently you'll fuel

• How much carbohydrate you'll consume

• Whether particular products should be taken with water

• Your caffeine strategy, if you're using one

Use long runs and race-specific sessions to reproduce your intended race-day routine as closely as possible.

If something repeatedly causes stomach issues in training, don't assume it'll suddenly work perfectly on race day.

What Should You Eat Before Running if You Have a Sensitive Stomach?

Pre-run nutrition is highly individual, but simpler is often better.

Before a key run or race, avoid experimenting with unfamiliar foods.

Many runners find that carbohydrate-focused meals that aren't excessively high in fat or fibre are easier to tolerate before prolonged exercise.

Large quantities of fat, fibre and protein can take longer to digest, which may contribute to gastrointestinal discomfort for some runners when eaten too close to exercise.

Timing matters too.

A large meal immediately before a hard session is much more likely to feel uncomfortable than a familiar meal eaten with sufficient time to digest.

Training is where you work out what to eat, how much to eat and how long before running works for you.

Gels Aren't Your Only Option

If you struggle with traditional energy gels, that doesn't mean you can't fuel effectively during longer runs.

There are several ways to consume carbohydrate while running, including:

• Energy chews

• Gummies

• Carbohydrate drinks

• Sports drinks

• Energy bars

• Sports beans

• Softer chewable fuel

Some runners prefer taking smaller amounts more frequently rather than consuming an entire gel at once.

Others find drinking some of their carbohydrate easier than eating it.

Our energy gels and running nutrition range includes gels alongside chews, gummies, carbohydrate drinks and other alternatives, so it's worth experimenting during training to find the format that suits you.

What About Maurten Hydrogel?

Some sports nutrition products take a different approach to carbohydrate delivery.

Maurten, for example, uses what it calls Hydrogel Technology in products such as its Gel 100 range. The concept is designed around delivering carbohydrate during exercise while addressing some of the gastrointestinal challenges athletes can experience with high carbohydrate intake.

That doesn't mean one product will automatically solve stomach problems for every runner.

Individual tolerance still matters, which is why even products designed with gastrointestinal tolerance in mind should be tested thoroughly during training.

You can explore the Maurten range and compare different gels and drink mixes as part of your training nutrition strategy.

What Should You Do if You Start Feeling Sick During a Run?

If you begin experiencing nausea or significant stomach discomfort, don't automatically continue forcing fuel into your stomach at the same rate.

Depending on the situation, slowing your intake temporarily, taking smaller amounts and reducing your running intensity may help.

If the problem occurs repeatedly during training, take note of:

What you ate beforehand

What products you used

How much you consumed

How quickly you consumed it

How much fluid you drank

The temperature and conditions

How hard you were running

Patterns often start appearing when you record what happened rather than treating each bad run as an isolated incident.

A Simple Troubleshooting Approach

If you're experiencing problems repeatedly, try changing one thing at a time.

If you're cramping:

Look at your training, pacing, muscular fatigue and hydration strategy rather than immediately assuming you need more salt.

If you're sweating heavily:

Estimate your sweat losses during training and experiment with an appropriate combination of fluid and electrolytes.

If your stomach is struggling:

Review how much carbohydrate you're consuming, how quickly you're consuming it and whether you've sufficiently practised that strategy.

Changing everything at once makes it almost impossible to work out what actually helped.

Build Your Strategy in Training

There is no perfect hydration or fuelling strategy that works for every runner.

One person may tolerate gels effortlessly while another prefers chews.

One runner may sweat extremely heavily while another experiences relatively modest fluid losses.

One athlete may cramp because they've pushed beyond what their legs are conditioned for, while another may be dealing with a combination of heat, fatigue and significant sweat losses.

Your goal during training is to gradually understand your own body.

Use long runs to practise.

Make small adjustments.

Keep track of what works.

By race day, your hydration and nutrition strategy should feel familiar rather than experimental.

The Takeaway

Cramping, heavy sweating and stomach problems can all interfere with running performance, but none of them necessarily has one simple cause.

Rather than looking for a miracle product, think about the bigger picture.

For cramping: consider muscular fatigue, pacing, conditioning and your hydration strategy.

For heavy sweating: understand your individual fluid losses and consider whether electrolytes should form part of your plan.

For stomach problems: practise your fuelling strategy during training and gradually determine how much carbohydrate, fluid and which products you tolerate best.

The more you practise your nutrition and hydration strategy alongside your physical training, the fewer surprises you're likely to encounter on race day.

Shop Energy Gels & Running Nutrition