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Hydration for Endurance Performance

22 Nov Hydration Strategies for Endurance Athletes

Posted at 05:27h in Articles, Fitness by

Proper hydration is essential for athletes to maintain performance, prevent dehydration, and optimize recovery. These guidelines provide evidence-based strategies tailored to endurance athletes and those engaging in prolonged physical activity.

Pre-Exercise Hydration

  • Consume 5–7 mL/kg of fluid containing sodium (20–50 mEq/L, equivalent to 460–1,150 mg/L, or 1.2–2.9 g/L of sodium chloride) at least 4 hours before an event or training session.1
  • If you fail to produce urine or notice dark, concentrated urine, drink an additional 3–5 mL/kg of fluid within 2 hours before the activity.1

Simplified Formulation for 1,000 mL Solution:

Carbohydrates: 30 g of sucrose & 15 g of maltodextrin (4.5% with a 2:1 glucose:fructose ratio)

Sodium: 1 g of sodium chloride (17.1 meq/L)

Potassium: 500 mg of potassium citrate (4.86 meq/L)

Magnesium: 250 mg of magnesium malate (1.6 meq/L)

This solution has an osmolarity of 262 mOsmol/L (hypotonic).

Rate of Fluid Consumption

Exercise Lasting 1–2 Hours:

Consume fluids at a rate of 0.15–0.20 mL/kg/min (~9–12 mL/kg/hour). For example, a 70 kg (154 lb) athlete should drink approximately 630–840 mL per hour, divided into portions every 10–20 minutes.3

Exercise Lasting Over 2 Hours:

Consume fluids at a rate of 0.14–0.27 mL/kg/min (~8–16 mL/kg/hour).3

Hydration During Exercise

Composition

Opt for a hypotonic carbohydrate-electrolyte solution2 with the following components:

  • Carbohydrates (CHO): Use multiple-transportable carbohydrates (MTC), such as a mix of glucose and fructose or sucrose (which breaks down into glucose and fructose), at a 4-6% concentration, with a 2:1 glucose-to-fructose ratio. If the drink is too sweet, replace glucose with maltodextrin, a polysaccharide that breaks down into glucose and provides a more sustained energy release.

* Research shows that MTC creates a greater osmotic gradient, enhancing water absorption compared to glucose alone,2 and CHO concentrations higher than 6% may slow the water absorption rate.2

  • Sodium: 15–20 mEq/L (~0.9–1.2 g/L of sodium chloride)
  • Potassium: 3–6 mEq/L (~300–600 mg/L of potassium citrate)
  • Magnesium: 1–2 mEq/L (81–162 mg/L of magnesium malate or 111–221 mg/L of magnesium citrate)

Simplified Equation: 

Fluid intake (mL/hour) = Body weight (kg) × 10

For high-intensity exercise or hot conditions, increase fluid intake by up to 50%.

Post-Exercise Rehydration

Replace fluids lost during exercise by drinking 1.5 L of water or an electrolyte solution for every kg of body weight lost (or 24 oz for every lb of body weight loss)1

REFERENCES

  1. Sawka, M.N., Burke, L.M., Eichner, E.R., Maughan, R.J., Montain, S.J., & Stachenfeld, N.S. (2007). American College of Sports Medicine position stand: Exercise and fluid replacement. Medicine & Science in Sports & Exercise, 39(2), 377–390.
  2. Rowlands, D.S., Kopetschny, B.H., & Badenhorst, C.E. (2022). The hydrating effects of hypertonic, isotonic, and hypotonic sports drinks and waters on central hydration during continuous exercise: A systematic meta-analysis and perspective. Sports Medicine, 52(2), 349–375.
  3. Holland, J.J., Skinner, T.L., Irwin, C.G., Leveritt, M.D., & Goulet, E.D.B. (2017). The influence of drinking fluid on endurance cycling performance: A meta-analysis. Sports Medicine, 47(11), 2269–2284.