Electrolytes Dosage: How Much to Take (Evidence-Based)

Electrolytes Dosage: How Much to Take (Evidence-Based)

Electrolytes — primarily sodium, potassium, magnesium, and chloride — are minerals that carry an electric charge and are essential for fluid balance, muscle contraction, and nerve signalling. When you sweat, you lose electrolytes alongside water, and the amounts lost vary substantially depending on sweat rate, duration, intensity, heat, and individual variation. Understanding electrolytes dosage therefore requires looking at your specific situation rather than applying a universal number.

Studied Effective Dose Ranges

Sodium is the most critical electrolyte to replace during prolonged exercise. Sweat sodium concentration varies widely between individuals, but typical losses run from roughly 20 to 80 mmol per hour during intense exercise (Maughan & Shirreffs, 2010). For practical supplementation, the American College of Sports Medicine recommends consuming sodium during exercise lasting over 60–90 minutes in warm conditions. Sports drinks typically provide 10–30 mmol sodium per 500 ml serving, which aligns with replacement needs for moderate to high sweat rates.

Potassium losses in sweat are lower than sodium on a concentration basis, but potassium plays a critical role in maintaining the resting membrane potential of muscle cells. Typical sweat losses are modest and are usually replaced adequately through normal food intake on rest days. During multi-day training blocks or prolonged heat exposure, supplemental potassium may be warranted.

Magnesium is lost in sweat and urine during exercise. Evidence suggests that athletes in heavy training are at greater risk of suboptimal magnesium status (Volpe, 2013). Supplemental magnesium is discussed in detail in the magnesium beginner's guide, but in the context of electrolyte replacement, 100–200 mg of elemental magnesium per day from a combined electrolyte product is within typical practice.

Dose by Goal

Upper Limits

Regulatory bodies in Europe set adequate intake levels for electrolytes — sodium's tolerable upper intake is around 2,300 mg/day for sedentary adults in most frameworks, though athletes can safely handle higher amounts due to sweat losses. Excessive sodium supplementation beyond genuine replacement needs is not beneficial and can contribute to high blood pressure in sodium-sensitive individuals.

For potassium, the generally recognised safe supplemental dose is up to 99 mg elemental potassium per serving in standalone supplements in many markets, though food provides much more. Individuals taking ACE inhibitors, ARBs, or potassium-sparing diuretics must consult a physician before supplementing potassium.

Timing Relative to Exercise

• Before: pre-hydrating with an electrolyte drink one to two hours before prolonged exercise helps begin the session in a state of adequate hydration. This is particularly relevant in heat.
• During: for exercise lasting more than 60–90 minutes, consuming an electrolyte drink every 15–20 minutes helps maintain plasma sodium and supports fluid absorption in the gut.
• After: post-exercise rehydration is more effective when sodium is present in the recovery drink, as it stimulates thirst and reduces urine losses (Shirreffs & Maughan, 1998).

Practical Protocol

For an active person training 4–5 times per week in moderate conditions:

1. Everyday baseline: dietary sodium from normal food covers baseline needs for most people.
2. Session up to 60 minutes: water is sufficient unless it is very hot.
3. Session 60–120 minutes: one serving of an electrolyte drink or tablet containing sodium and potassium during training.
4. Session over 120 minutes or hot conditions: begin electrolyte intake from 30–40 minutes in; consider 300–600 mg sodium per hour from drink plus food.
5. Post-training: rehydrate with electrolyte drink if sweat losses were significant; pair with a carbohydrate-protein meal.

At maxfit.ee, you can find products like OstroVit Electrolyte 90tabs, OstroVit Pure Electrolytes 270g, and PowerBar 5 Electrolytes 10tabs Vaarika-granaatõuna in the elektroluudid category.

FAQ

Do I need electrolytes if I only train for 45 minutes?

For most people, a 45-minute moderate-intensity training session in a cool environment does not require electrolyte supplementation — water is sufficient. Electrolyte drinks become relevant primarily for sessions lasting over 60–90 minutes, in heat, or for individuals with very high sweat rates.

Can you take too many electrolytes?

Yes. Excessive sodium intake beyond genuine replacement needs contributes no performance benefit and may cause fluid retention. Excessive potassium supplementation is potentially dangerous for individuals with impaired kidney function or those on certain medications. Stick to replacement rather than mega-dosing.

Is it better to get electrolytes from food or supplements?

For the general active population, dietary electrolytes (from vegetables, fruits, dairy, and salted foods) cover daily needs. Electrolyte supplements provide a convenient, measured dose for during and immediately after prolonged exercise sessions, particularly when appetite is suppressed.

References

Maughan, R. J., & Shirreffs, S. M. (2010). Dehydration and rehydration in competitive sport. Scandinavian Journal of Medicine & Science in Sports, 20(Suppl 3), 40–47.

Shirreffs, S. M., & Maughan, R. J. (1998). Volume repletion after exercise-induced volume depletion in humans: replacement of water and sodium losses. American Journal of Physiology, 274(5), F868–F875. https://pubmed.ncbi.nlm.nih.gov/9612323/

Volpe, S. L. (2013). Magnesium and the athlete. Current Sports Medicine Reports, 12(4), 208–213.