• Pharmaceutical Oral Rehydration Solutions (ORS) and sports-related Electrolyte Replacement Supplements are available in ready to drink, tablet, ice block and powdered forms in a wide variety of flavours.
  • In general, ORS are manufactured according to the World Health Organisation guidelines for the treatment and prevention of dehydration associated with diarrhoea and gastroenteritis. Typical sodium content is in the range of 50-60mmol/L which is ideal for electrolyte and fluid replacement following large losses. Note that sweat sodium concentrations are often less than this value, and therefore exclusive reliance on high sodium ORS products with no plain water intake during ultra-endurance exercise could result in increased blood sodium concentration, due to replacing proportionally more sodium than fluid. -
  • Since ORS are focused on electrolyte/fluid replacement; the low-moderate carbohydrate content (1.5-2% or 1.5-2 g/100 ml) is present to contribute to intestinal sodium/fluid absorption rather than achieve typical fuelling goals for exercise.
• Sports-related electrolyte supplements which are marketed to athletes include:
  • Electrolyte-only powders and tablets which can be added to fluids varying in carbohydrate content according to the athlete’s needs.
  • Sport drinks with high electrolyte concentrations (often marketed as an “endurance formula” which provide higher amounts of both carbohydrates and electrolytes. The sodium content of these drinks is typically within the range of 30-50 mmol/L (in contrast to typical ranges of 10-30 mmol/L in standard sports drinks)

Note that the characteristics of sports drinks are discussed in a separate Sports Drinks (Carbohydrate-Electrolyte drinks) fact sheet)

Table 1: A sodium ready reckoner of common high sodium foods

Food First approach - The following meals provide ~60mmol of sodium (the equivalent to 1litre of an ORS) as well as other important nutrients. -

• Vegemite and cheese on toast ^{C P Ca}: 2 slices white bread + 2 slices cheese + 1 teaspoon vegemite
• Baked beans on toast ^{C P}: 2 slices white bread + ½ 220g tin
• Ham, cheese & pickle sandwiches ^{C P Ca}: 2 slices white bread + 1 slice cheese + 1 tablespoon pickle spread
• Smoked salmon & olive salad ^{C P I}: 1 slice smoked salmon + 5 olives
• Cheese, crackers & pretzels ^{C P Ca}: 1 cup pretzels + 3 slices cheese + 2 rows of rice crackers
• Cereal & toast ^{C P Ca}: 1 ½ cups cornflakes + 1 ½ cups milk + 2 x toast + 1 Tablespoon peanut butter
• Tuna, cheese & salad wrap + nuts ^{C P Ca} I: 1 wrap + 1 x 90g tin tuna + 1 slice cheese + salad + 1 teaspoon butter + 1/3 cup peanuts

^C provides valuable amounts of carbohydrate to support post-exercise refuelling

^P provides valuable amounts of protein to support post-exercise repair

^I provides valuable amounts of iron to support overall athlete health and performance

^Ca provides valuable amounts of calcium to support overall athlete health and performance