The term “electrolytes” refers to substances that have either a natural positive or negative charge when dissolved in water. The average adult’s body is about 60 percent water, with every fluid and cell utilizing electrolytes for chemical reactions, fluid balance, and helping the heart, brain, muscles, and nerves to function.

Electrolytes can be found in foods that we eat and drink. To keep them in balance, the kidneys filter out excess and excrete electrolytes from the body via urine or more rapidly via sweat. Symptoms like muscle cramps, fatigue, or dizziness, especially after exercise, could be a sign of electrolyte imbalance.

When taking part in intense or endurance exercise (longer than 75 minutes), electrolytes are lost via sweat, the body’s primary cooling mechanism. Athletes at higher altitudes or those exerting themselves with heavy gear may also benefit from electrolyte supplementation because staying hydrated in those conditions can be more challenging. During these times, a body may need the help of an electrolyte replacement to maintain balance. For most people, moderate and low-intensity physical activity often doesn’t require supplementation beyond hydration (water).

What are some primary electrolytes and what do they do? 

  • Sodium (Na): Restores the body’s fluid-electrolyte balance, so keeping sodium intake balanced with losses (primarily from sweat) is important. There is a lot of variation in salt concentration in sweat; it can range from 200 milligrams (mg) to 2,000 mg per liter of sweat. Age can also play a role, as kids become dehydrated after losing 1 percent of their fluid levels, while adults are alright until around 2 percent loss. Teenagers may become dehydrated faster than younger kids because puberty changes sweat output. Water alone can quench thirst quickly, while high levels of sodium make a person want to drink more to hydrate. Ideally for adults, sodium levels around 150 mg per 12 ounce bottle is recommended for replacement.
  • Chloride (Cl): Regulates fluids, helps with nerve function and muscle contraction, and acid-base balance (pH) in the body. Chloride is lost through sweat. The maximum recommended daily intake for chloride is 3,100 mg, which is roughly equivalent to a teaspoon of table salt. Replenishment can be achieved through electrolyte-containing drinks or foods.
  • Potassium (K): Helps with nerve function, muscle contraction (including the heart muscle), and maintains fluid and electrolyte balance inside cells. Daily recommendations for potassium intake are around 2,600-4,700 mg for adults. Supplements in the US should not exceed 99 mg per serving. Lost potassium can be replenished by consuming potassium-rich foods like bananas, potatoes, and leafy greens, or electrolyte supplements.
  • Calcium (Ca): Vital for bone and teeth health, muscle function (including heart muscle), nerve transmission, and blood clotting. Minimal calcium is lost during exercise and supplements over 1000 mg per day should be avoided. Leafy greens and fortified foods can maintain the recommended intake.
  • Magnesium (Mg): Involved in over 300 enzymatic reactions in the body, including energy production, muscle function, nerve function, and bone health. Magnesium is lost through sweat during exercise. Daily intake recommendations for adults are around 310-420 mg. Nuts, seeds, whole grains, and dark chocolate can help replenish magnesium during and after exercise.
  • Phosphorus (P): Supports bone and teeth health, energy production (as adenosine triphosphate – ATP), cell membrane structure, and pH balance. Phosphorus is only minimally lost through sweat and too much can be consumed, with an upper limit of 4000 mg per day for most adults. Most people can get this from a balanced diet including dairy, fish, meat, and whole grains.
  • Carbohydrates: These are not an electrolyte, but are commonly managed alongside electrolytes as an energy source for high-intensity or endurance athletes. Sugars are the most energy-available form of carbohydrate and help the body and brain with a quick energy source when it may be depleting, but are unnecessary if simply looking for hydration. Sugars are ideally 6-8 percent of “total carbohydrates” on the nutrition facts label for energy replacement.

Powdered drink mix is being added to a glass of water with a plastic scoop

Photo: Adobe Stock

Types of electrolyte products

In addition to food sources, electrolytes can be supplemented, often through beverages or powders to support recovery. There are a lot of electrolyte powders and drinks to choose from:

  • Sports drinks are best used for high intensity or endurance sports. Watch out for high sugar levels.
  • Hydration-boosting powders or tablets are good for hydration and lighter-intensity activity as they are lower or sugar-free. Sodium content can vary widely, and these products may have artificial sweeteners or vitamins added.
  • Recovery or performance powders support both rehydration and muscle recovery post-exercise. These often include or combine with protein (amino acids) and carbohydrates, making them higher-calorie choices.

"Before-During-After" is a common mantra for hydration surrounding exercise, meaning that simply drinking water during a workout is not enough. A basic outline for hydration surrounding high intensity exercise is:

  • Two hours before intense activity: have 24 ounces of a sports drink or electrolyte-infused water.
  • During exercise: hydrate as the activity allows to quench thirst.
  • Post-exercise: 16-24 ounces (approximately 24 ounces per pound lost) of water, sports drink, or electrolyte-infused water. A tailored electrolyte plan is likely desirable for more intense athletic endeavors.

The bottom line

As electrolytes are water soluble, and excess is excreted over time, most healthy people are not at high risk of over consuming them. Water is often sufficient for most low-to-moderate-intensity athletes. Those with high blood pressure or kidney disease, however, should work closely with a doctor or registered dietitian to ensure they are consuming a safe amount of electrolytes. Be food label savvy, including checking for added vitamins, minerals, and other “performance enhancers” that may result in over-supplementation and associated toxicity. As with any dietary change or supplement, let health providers know if this is a regular part of a diet.

 

Emma Smith, MS, RD is an outpatient dietitian and has a Master’s degree in Food Systems Leadership.