Electrolyte Calculator
Use your workout length, effort and conditions to see whether you’re likely to need more than water.
Could electrolytes help for this workout?
Tell us how long you’ll exercise, how hard it’ll feel and how much you tend to sweat.
Describe the session to see whether water is likely enough or electrolytes may be worth considering.
Safety: electrolytes include sodium, potassium and other minerals. Sweat sodium varies greatly, and salt marks are not a laboratory measurement. Follow product directions; sodium cannot make excessive fluid intake safe. Seek individual advice for medical conditions or medicines affecting fluid balance.
What your result means
The calculator looks at how long and hard you’ll train, how warm it is and how much you tend to sweat. If you have a measured sweat rate, you can add it too. The result helps you decide whether to consider electrolytes for this session.
Sodium and chloride are the main electrolytes you lose in sweat. The amounts vary a lot between people. Salt marks on your kit can give you a clue. You need a sweat-sodium test to estimate the amount more closely. Water and ordinary meals may cover shorter sessions, while longer or hotter sessions can make a familiar electrolyte drink more useful.
Worked example
A 90-minute hard run in warm conditions
A 90-minute run like this may make electrolytes worth considering, especially if you sweat heavily. If your sweat rate is 0.8 litres per hour, you’d lose about 1.2 litres of sweat. To work out how much sodium the sweat contains, you’d need a separate measurement.
Check the label for the drink as you’ll prepare it and try it in training. Keep the total you drink below the amount you’ve measured losing. See when electrolytes might help.
Electrolyte questions
Do I need electrolytes during exercise?
Water and your usual meals often cover a short, easy session. Electrolytes may be more useful if you train longer or harder, exercise in the heat or sweat heavily.
When is water enough?
Water is usually enough for a shorter session in mild weather when you can eat your usual meals.
Do electrolytes help during long runs?
They can help replace sodium lost in sweat on a long run. Try both the product and your drinking plan during training first.
What electrolytes are lost in sweat?
Sodium and chloride are the main electrolytes lost, with smaller amounts of potassium and other minerals. How much you lose can vary a lot.
Can you consume too many electrolytes?
Yes. Follow the directions on the product. If a health condition or medicine affects your fluid or sodium balance, ask your healthcare team for advice.