Electrolytes: what they are and when you need them
Electrolyte powders, tablets and drinks are everywhere now, often sold with big promises. Your body does need electrolytes, but most days, normal food and water give you enough. Here is when you really need extra, and what to choose.
Quick answer
- Electrolytes are minerals like sodium, potassium, chloride, magnesium and calcium that carry an electric charge and control fluid balance, nerves and muscles.
- Most healthy people get enough from normal meals and water.
- You need extra in diarrhoea or vomiting, after heavy sweating in the heat, or during long hard exercise. ORS is the best choice for illness.
- Many sports and "electrolyte" drinks contain a lot of sugar and are not needed for normal daily life.
What do electrolytes do?
| Electrolyte | Main job | Good food sources |
|---|---|---|
| Sodium | Keeps water in the blood, helps nerves and muscles work | Salt, most cooked food (we usually get too much) |
| Potassium | Heart rhythm, muscles, lowers blood pressure | Banana, coconut water, potatoes, tomatoes, daal, dahi, spinach, dried apricots |
| Chloride | Fluid balance, stomach acid | Salt |
| Magnesium | Muscles, nerves, energy, sleep | Nuts, seeds, whole grains, bajra, daal, leafy greens |
| Calcium | Bones, teeth, muscle contraction | Milk, dahi, paneer, ragi, til (sesame), leafy greens |
Your kidneys keep these minerals in balance very carefully. When you eat more salt, you get thirsty and pass more urine. When you sweat, you lose some sodium and a little potassium.
When do you need extra electrolytes?
- Diarrhoea or vomiting. This is the most important one. You can lose a lot of water and salts quickly. Dehydration from diarrhoea is still a major cause of illness in children in South Asia.
- Heavy sweating in hot weather, especially for people working outdoors for many hours. See how much water to drink in hot summers.
- Long, hard exercise, more than about 60 to 90 minutes, such as a long run, football match or cricket in the heat.
- After a fever with a lot of sweating.
For a normal day at the office or a 30 minute walk, water and normal meals are enough.
Signs you may be low on fluids and electrolytes
- Very thirsty, dry mouth
- Dark yellow urine, or passing very little urine
- Headache, tiredness, weakness
- Dizziness, especially when standing up
- Muscle cramps
- In children: fewer wet nappies, no tears when crying, sunken eyes, very sleepy
ORS: the best electrolyte drink for illness
Oral rehydration salts (ORS) are one of the greatest medical discoveries of the last century. The WHO and UNICEF formula has the right mix of salt and sugar, which helps the gut absorb water faster than plain water alone. ORS is cheap and sold in every pharmacy in Pakistan and India.
- Mix one packet in exactly the amount of clean water written on the packet (usually 1 litre or 500 ml for smaller packs). Too little water makes it too salty.
- Sip slowly and often. For a child, give small spoonfuls every few minutes.
- Use within 24 hours after mixing, then make fresh.
- For children with diarrhoea, doctors also give zinc tablets for 10 to 14 days.
Homemade ORS (if you cannot get a packet)
The WHO and UNICEF give this simple home recipe:
- 1 litre of clean, boiled and cooled water
- 6 level teaspoons of sugar
- Half a level teaspoon of salt
Stir until dissolved. Measure carefully. Too much salt can be harmful, especially for babies. Packet ORS is safer and better when available.
ORS vs sports drinks vs electrolyte powders
| Drink | Sodium (per litre) | Sugar (per litre) | Best for |
|---|---|---|---|
| WHO ORS | About 1,700 mg | 13.5 g | Diarrhoea, vomiting, heat illness |
| Typical sports drink | 400 to 500 mg | 50 to 60 g | Long, hard exercise |
| Electrolyte tablets and powders | Varies (200 to 1,000 mg) | Often 0 to low | Heavy sweating, long exercise |
| Coconut water | 250 to 1,000 mg (varies a lot) | 25 to 60 g (natural) | A tasty drink rich in potassium, but lower in sodium than ORS |
| Salty lassi or nimbu pani with salt | Depends on the salt | Low if no sugar | Hot days |
Sports drinks are not good for diarrhoea, because they have too much sugar and too little salt, which can make diarrhoea worse. And for everyday drinking, they add a lot of sugar: a 500 ml bottle can have 6 to 7 teaspoons. Read zero calorie soft drinks for more on sweet drinks.
Natural ways to get electrolytes
- Banana, coconut water and dates for potassium
- Dahi, lassi and milk for calcium, potassium and some sodium
- Daal, nuts and whole grains for magnesium
- A pinch of salt in nimbu pani or lassi on very hot days
- Watermelon, cucumber and tomatoes for water and potassium
Can you have too many electrolytes?
Yes. Taking a lot of electrolyte tablets or drinks when you do not need them can cause problems:
- Too much sodium can raise blood pressure. Most of us already eat too much salt. See low sodium salt.
- Too much potassium can be dangerous for people with kidney disease or those on certain blood pressure medicines.
- Too much magnesium from supplements can cause diarrhoea.
If you have kidney disease, heart failure or high blood pressure, ask your doctor before using electrolyte products.
Common questions
Should I drink electrolytes every day?
Most people do not need to. Water and normal meals give you enough. Electrolyte drinks are useful during illness with diarrhoea or vomiting, heavy sweating in the heat, or long hard exercise.
Is coconut water a good electrolyte drink?
It is a healthy drink rich in potassium, but it has less sodium than ORS and the amount varies a lot, so it is not a full replacement for ORS during diarrhoea.
Can I give ORS to my child?
Yes. ORS is safe and recommended for children with diarrhoea. Mix it exactly as written on the packet and give small sips often. See a doctor if the child is very sleepy, not drinking, or has blood in the stool.
Do electrolyte drinks help with hangovers or tiredness?
Only if you are dehydrated. For normal tiredness, rest, sleep, water and food are what help.
Sources
- World Health Organization and UNICEF. Oral rehydration salts: production of the new ORS. Geneva, 2006. www.who.int/publications
- World Health Organization. Diarrhoeal disease, fact sheet. www.who.int/news-room/fact-sheets/detail/diarrhoeal-disease
- Sawka MN, Burke LM, Eichner ER, et al. American College of Sports Medicine position stand: exercise and fluid replacement. Medicine & Science in Sports & Exercise, 2007;39:377-390. doi.org/10.1249/mss.0b013e31802ca597
- Institute of Medicine (National Academies). Dietary Reference Intakes for water, potassium, sodium, chloride, and sulfate, 2005. doi.org/10.17226/10925
- NIH Office of Dietary Supplements. Potassium and magnesium fact sheets for consumers. ods.od.nih.gov
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