Electrolytes: do you need them?

When plain water is enough

For the vast majority of gym sessions, you do not need an electrolyte drink. A 45 to 60 minute strength or conditioning session followed by a normal meal will not drain your sodium in any meaningful way. The food you eat afterwards replaces what you lost.

The typical UK diet already contains plenty of salt. The NHS says adults should eat no more than 6 g of salt a day, about a teaspoon, and most people exceed that. Adding electrolyte tablets to every glass of water on top of a normal diet can push intake higher still, which is not ideal for blood pressure.

A simple way to tell whether you need more is to look at how you feel after long sessions. If you finish a two hour weekend session with a headache, feeling washed out and craving salty food, a little more sodium during or after training may help. If you feel fine, you probably do not need to change anything.

When electrolytes are worth it

Electrolytes start to make sense when you lose a lot of fluid and salt, or when you will be drinking a lot of water over several hours.

• Long sessions: roughly 90 minutes or more of continuous hard work, such as a long run, a full HYROX simulation or a race.
• Heavy sweaters: if you finish sessions soaked through and lose more than 1 to 1.5 kg of body weight.
• Salty sweaters: if you see white salt marks on your kit or skin, or sweat stings your eyes.
• Hot, humid conditions: summer sessions and indoor events with a lot of people in a warm hall.
• Training twice in a day: where you need to rehydrate fast between sessions.
• After illness: vomiting or diarrhoea, where oral rehydration solutions from a pharmacy are the right tool.

Our guide to hydration for training explains how to measure your sweat rate, which tells you whether you fall into the heavy sweater group.

Choosing a product, or making your own

The main thing to look at on the label is sodium per serving. Products vary widely, from low-dose tablets aimed at everyday drinking to high-dose sachets for endurance athletes. For long training and racing, a moderate-strength drink that you have tested in training is usually the safe middle ground.

• Electrolyte tablets: low calorie, easy to carry, good for long sessions where you do not need extra fuel.
• Sports drinks: combine carbohydrate with electrolytes. Useful for long, hard efforts where you also need energy.
• Homemade: diluted fruit squash or juice with a small pinch of salt works for many people and costs very little.
• Food: a salty snack such as pretzels or a salted rice cake after a very sweaty session does a similar job.

For race day, practise your chosen drink in training first. Our HYROX race day nutrition guide covers how to fit fluids and fuel around the stations. If you are preparing for a race through the HYROX training at Lycan Strength, use your longest sessions to test the exact drink, the amount and the timing you plan to use on the day.

Do electrolytes stop cramp?

This is the question most people are really asking. The honest answer is that exercise cramp is still not fully understood, but the evidence points more towards muscle fatigue and nerve signalling than to low sodium or magnesium. Cramp often strikes in the muscles working hardest, late in a session or when you push beyond your usual pace.

Heavy salt losses may play a role for some people, especially in long events in the heat, which is why some athletes find electrolytes help. For most, better pacing, more specific training for the event and arriving well fuelled make a bigger difference than tablets.

Night cramps in the calves are common, particularly with age, and are not usually caused by training. If you get frequent, severe or unexplained cramps, speak to your GP, as some medicines and medical conditions can cause them.

Who should check with a GP first

Some people should not increase their salt or electrolyte intake without advice. Speak to your GP or a registered dietitian before using electrolyte products regularly if you:

• Have high blood pressure or take medication for it
• Have heart failure or kidney disease
• Have been told to limit salt, potassium or fluids
• Take diuretics or other medicines that affect fluid balance
• Are pregnant and considering high-dose products

Magnesium supplements in particular can cause diarrhoea at higher doses and interact with some medicines. If you are generally well and training normally, a balanced diet with plenty of vegetables, fruit, whole grains, nuts and dairy covers potassium, magnesium and calcium without needing tablets. Our guide to eating more vegetables is a good place to start.