During endurance training sessions, it is recommended to consume sodium and in some cases potassium where training is intense and of a lengthy duration such as 5 hours. Sodium losses are greater than potassium and if these are not replaced hyponatremia can set in. These electrolytes are responsible for maintaining a proper fluid balance, transmission of nerve impulses and muscle contractions (Fink, Mikesky & Burgoon, 2012).
In addition to sodium and potassium, it is best to use a source of multiple transportable carbohydrates including both fructose and glucose. It is also recommended that athletes consume small amounts of these carbohydrates frequently, and if possible to tolerate, it is best to drink 200-300ml every 15-20 minutes according to the workout intensity (AIS Sports Nutrition, 2014).
For maximum fluid uptake and refuelling, sports drinks containing 4-8% carbohydrate and 10-20 mmol/L sodium are recommended. Check the potassium levels and if necessary, carry a banana or orange to use during exercise. Additional factors to keep in mind in decision making include affordability, convenient packaging and flavour (Fink, Mikesky & Burgoon, 2012; AIS Sports Nutrition, 2014).
Examples of sports drinks and carbohydrate/sodium levels are listed in the table below:
|Drink||Carbohydrate (%)||Sodium (mmol/L)|
|PB Fluid & Electrolyte Replacement||6.8||25|
(Source: AIS Sports Nutrition, 2009)
AIS Sports Nutrition (n.d). Carbohydrate Loading Fact Sheet. Australian Government: Department of Sports Nutrition.
AIS Sport Nutrition. (2009). Fluid – who needs it. Australian Government: Department of Sports Nutrition. Retrieved from https://www.ausport.gov.au/ais/sports_nutrition/fact_sheets/fluid_-_who_needs_it
Fink, H., Mikesky, A. and Burgoon, L. (2012).Practical Applications In Sport Nutrition (3rd Ed.). Jones & Bartlett Publishers.