Protocols › Electrolytes

Electrolytes for endurance exercise

Goal: To keep up performance in exercise longer than 1 hour, as trials of carbohydrate-electrolyte drinks did.

Each protocol describes what studies used, for one goal or for one group of people. It is not advice for you: talk to a doctor before you start a supplement.

Updated 9 Nov 2026
Dose

0.15 to 0.20 mL of fluid per kg of body weight per minute in cycling of 1 to 2 hours. In longer rides: drinking to thirst, or 0.14 to 0.27 mL per kg per minute.[1]

Form

Sports drink with carbohydrate and electrolytes. Drinks less concentrated than blood kept blood volume best.[2][3]

When to take

During exercise that lasts more than 1 hour. In hard cycling of 1 hour, drinking lowered performance by 2.5%.[1]

How long

One exercise session at 22 °C or warmer.[2]

What studies found

21 studies, 316 people: a small gain against water or a dummy drink (Hedges' g 0.37), clearest for aerobic endurance (g 0.45).[2] 9 cycling studies: performance up 2.1% in moderate rides of 1 to 2 hours and 3.2% in rides over 2 hours, against no drinking.[1]

Ask a doctor first

Drinking more than thirst asks in long events can lower blood sodium. This can happen in as many as 2% to 7% of people in endurance events, and a severe case is a medical emergency.[4][5] In a trial of 413 Ironman athletes, blood sodium was the same with salt tablets, dummy tablets or no tablets.[6] Ask a doctor or pharmacist first if you have kidney disease, high blood pressure or take a medicine that keeps potassium in the body.[7][8]

References

  1. The Influence of Drinking Fluid on Endurance Cycling Performance: A Meta-Analysis. Holland JJ, Skinner TL, Irwin CG, Leveritt MD, Goulet EDB Sports Med, 2017. PMID 28497286
  2. Effects of Acute Carbohydrate-Electrolyte Supplementation on Exercise Performance in Moderate-to-Hot Ambient Conditions: A Systematic Review and Meta-Analysis. Wang X, Liang T, Liu Y, Zhang X, Zhao S, Liang Z, et al. Nutrients, 2026. PMID 42884651
  3. The Hydrating Effects of Hypertonic, Isotonic and Hypotonic Sports Drinks and Waters on Central Hydration During Continuous Exercise: A Systematic Meta-Analysis and Perspective. Rowlands DS, Kopetschny BH, Badenhorst CE Sports Med, 2022. PMID 34716905
  4. Exercise-associated hyponatremia. Rosner MH Semin Nephrol, 2009. PMID 19523574
  5. Exercise-Associated Hyponatremia. Hew-Butler T Front Horm Res, 2019. PMID 32097926
  6. Sodium supplementation is not required to maintain serum sodium concentrations during an Ironman triathlon. Hew-Butler TD, Sharwood K, Collins M, Speedy D, Noakes T Br J Sports Med, 2006. PMID 16505084
  7. Potassium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. ods.od.nih.gov
  8. Summary - Dietary Reference Intakes for Sodium and Potassium. National Academies of Sciences, Engineering, and Medicine National Academies Press (NCBI Bookshelf), 2019. www.ncbi.nlm.nih.gov