June 28, 2026, 6:11 am | Read time: 4 minutes
On hot summer days, many people turn to electrolyte drinks. On social media, they are considered a real insider tip for compensating fluid loss. But does the body actually need additional electrolytes in the heat, or is “normal” water sufficient? FITBOOK asked an expert when additional intake might be beneficial and what really matters in high temperatures. FITBOOK Editor-in-Chief Nuno Alves also has an opinion on this.
What Electrolytes Do in the Body
Electrolytes are minerals dissolved in body fluids and are essential for numerous bodily functions. The most important include sodium, potassium, magnesium, calcium, chloride, phosphate, and bicarbonate. They ensure, among other things, that nerve impulses are transmitted, muscles can work, and the water and acid-base balance remain stable.
Cardiologist Explains When Electrolytes Are Really Useful in Heat
With significant fluid loss–such as from prolonged endurance activities, physical work in high heat, or illnesses with diarrhea and vomiting–the body loses not only water but also larger amounts of electrolytes. In such situations, it can be beneficial to replace them specifically.
Cardiologist Dr. Christopher Schneeweiss explains: “There are now a variety of electrolyte products. However, I don’t believe everyone needs them–even if someone does strength training twice a week and doesn’t sweat significantly.”
It’s different with longer, intense exertion, especially in endurance or performance-oriented areas and at high temperatures: “Those who sweat a lot lose not only fluid but also electrolytes like sodium, magnesium, and potassium. Pure water hardly compensates for this loss. Under such conditions, it can be useful to specifically supply electrolytes to maintain performance,” Schneeweiss explains.
Sodium Deficiency Can Be Dangerous in Extreme Cases
In very long and intense exertions, sodium deficiency can occur in rare cases. This can have serious consequences.
Schneeweiss says: “In very long and intense exertions, hyponatremia, or sodium deficiency, can occur in extreme cases–a potentially dangerous situation. However, in everyday life, this rarely happens because the body usually develops a natural craving for salty foods in time.”
Not Only Athletes Should Be Attentive
Even outside of sports, there are situations where the electrolyte balance can become disrupted–such as in older people or during the use of diuretic medications.1
“It’s also important: Heavy sweating without physical exertion is usually unproblematic in the short term. However, caution is advised if diuretic medications like diuretics are also taken or if the natural sense of thirst diminishes with age,” warns the cardiologist.
Also interesting: 7 study-based hacks to cool down the body in heat in time
For FITBOOK Editor-in-Chief, the Need Is Individual
FITBOOK Editor-in-Chief Nuno Alves also regularly deals with topics of training, nutrition, and health. He explained to us when he considers additional electrolyte intake to be useful.
“I only take additional electrolytes in exceptional cases. For example, on days when I plan longer workouts or in high temperatures. Then I add a mix of about 600 milligrams (mg) of sodium, 300 mg of potassium, and 40 mg of magnesium to my drink, which consists of mineral water and the juice of a lemon. Generally, I make sure to get enough electrolytes through my diet.”
Alves also emphasizes that electrolytes are not part of every training session for him: “I don’t see electrolytes as a fixed component of every workout–also because not every session leads to significant fluid and sodium loss. This is also very individual: Those who sweat a lot usually lose more electrolytes and might consider supplementation. A hint can be that sweat tastes noticeably salty or white residues are visible on clothing. But even that doesn’t replace a precise assessment.”
How to Recognize an Electrolyte Deficiency
When Does Sweating Become Dangerous?
These Foods Provide Important Electrolytes
Electrolytes are usually absorbed through food and drinks. A balanced diet provides sufficient sodium, potassium, magnesium, and other minerals in most cases.
Potassium is found in apricots, bananas, avocados, tomatoes, and dried fruits. Magnesium is provided by whole grain products, legumes, and green leafy vegetables. Sodium and chloride are mainly absorbed through table salt. For healthy people, additional intake of electrolyte supplements is usually not necessary.2
Muscle Cramps and Dizziness Can Be Warning Signs
If large amounts of electrolytes are lost over a longer period and not replaced, it can lead to muscle cramps, muscle weakness, exhaustion, headaches, nausea, or circulatory problems. Since these symptoms can have many causes, an actual electrolyte deficiency can only be determined through medical examinations.
In conclusion, Schneeweiss emphasizes: “My conclusion: For most people, it’s enough to drink plenty of water. However, those who sweat heavily over a long period should also ensure an adequate intake of electrolytes.”