Most people don’t need to take electrolytes at all. If you eat a reasonably balanced diet, your body already gets enough sodium, potassium, magnesium, and calcium from food and drinks throughout the day. Your kidneys constantly filter and balance these minerals, sending any excess into your urine. Supplemental electrolytes only become useful in specific situations: prolonged exercise, heavy sweating, illness, or certain diets that shift how your body handles fluids.
When You Don’t Need Them
For everyday life with moderate activity, plain water and regular meals cover your electrolyte needs. The adequate daily intake for adults is about 1,500 mg of sodium, 2,600 to 3,400 mg of potassium, 310 to 420 mg of magnesium, and 1,000 to 1,200 mg of calcium, depending on age and sex. Most people hit these numbers (and often exceed them, especially for sodium) without trying.
If your workout lasts less than 75 minutes and isn’t extremely intense, water alone is sufficient. There’s no physiological benefit to adding electrolytes to a casual gym session, a short run, or a yoga class. Drinking a sports drink in these cases just adds sugar and sodium you don’t need.
During Exercise Over 60 to 90 Minutes
Once you cross the 60 to 90 minute mark, especially at moderate to high intensity, your body starts losing enough sodium through sweat that plain water becomes less effective at keeping you hydrated. A sports drink with both carbohydrates and electrolytes is appropriate during these sessions. You don’t need to follow a rigid schedule. Sipping steadily throughout the workout, rather than gulping large amounts at once, keeps your fluid balance more stable.
For endurance efforts lasting two to three hours or more, such as marathons, long cycling rides, or hiking in heat, you’ll want a product specifically designed for endurance athletes, which contains higher concentrations of sodium and other minerals. This is especially true if you’re a “salty sweater,” someone who notices white salt residue on their skin or clothes after exercise. In that case, eating a salty snack or drinking a sports drink before exercise is also worthwhile.
After a long or intense session, don’t just chug plain water. Water without sodium passes through your body faster and is retained less effectively. Pair your post-workout water with salty foods like pretzels, mixed nuts, or crackers, or use a recovery drink that contains electrolytes.
During Illness With Vomiting or Diarrhea
Gastroenteritis and other illnesses that cause vomiting or diarrhea deplete electrolytes rapidly. In these situations, frequency matters more than volume. Adults should take small, frequent sips of an oral rehydration solution rather than drinking large amounts at once, which can trigger more vomiting. After each episode of diarrhea, aim for about 100 to 240 ml (roughly half to one cup) of rehydration fluid.
For children, the approach is even more cautious. Start with just one teaspoon to one tablespoon of liquid at a time, offered every 5 to 15 minutes. If the child tolerates that, gradually increase. Infants under six months can work up to 30 to 90 ml per hour, while children over two can handle 180 to 250 ml per hour. If vomiting returns, take a 30 to 60 minute break and start again.
In Hot and Humid Conditions
Heat and humidity increase your sweat rate, which increases electrolyte loss. But if you eat a normal diet, you typically don’t need extra electrolytes just because it’s hot outside. The exception is the first few days of heat exposure, before your body acclimates. During that adjustment period, your sweat contains higher concentrations of sodium, and a sports drink or salty snack can help bridge the gap.
Once you’re acclimated (which generally takes one to two weeks of regular heat exposure), your body becomes more efficient at conserving sodium in sweat. At that point, the same rules as exercise apply: if you’re active for more than 60 to 90 minutes in the heat, add electrolytes. If you’re just going about your day, food and water are enough.
On a Low-Carb or Ketogenic Diet
Low-carb and ketogenic diets create a unique situation. When you drastically reduce carbohydrates, your body excretes more sodium through the kidneys, which can drag potassium and magnesium down with it. This is why many people on keto experience headaches, fatigue, and muscle cramps in the first few weeks, often called “keto flu.”
People eating very low-carb often need 3 to 7 grams of sodium per day, roughly double what’s recommended for the general population. A practical approach is dissolving a teaspoon of salt in a liter of water and sipping it throughout the day, or drinking a cup or two of broth or bouillon (which provides about 1 gram of sodium per cup). If you exercise on keto, adding half a teaspoon of salt to water about 30 minutes before your workout can improve performance.
For potassium, aim for 3,000 to 4,700 mg daily, prioritizing potassium-rich foods like avocados, leafy greens, and salmon. Supplements are an option but are sold in small 99 mg tablets, so food sources are far more efficient. Magnesium supplementation of up to 400 mg daily is generally safe, but take it with food to avoid digestive discomfort.
Signs You’re Getting Too Much or Too Little
The tricky thing about electrolyte imbalance is that too much and too little can look almost identical. Both ends of the spectrum can cause fatigue, nausea, headaches, muscle cramps, and an irregular heartbeat. Confusion, numbness or tingling in your hands and feet, and persistent muscle weakness are also warning signs.
Severe imbalances, whether from overloading on supplements or from significant depletion, can lead to seizures or dangerous heart rhythm problems. This is why “more is better” doesn’t apply to electrolytes. If you’re supplementing daily without a clear reason (you’re not exercising heavily, eating low-carb, or recovering from illness), you may be pushing your levels higher than your kidneys can comfortably manage.
The simplest guideline: let the situation dictate the frequency. Most days, your food handles it. On days involving extended exercise, heavy sweating, illness, or a carb-restricted diet, add electrolytes during and after the period of increased demand, then return to your normal routine.