How Sodium Helps Keep Athletes Hydrated

Wemple RD, TS Morocco, and GW Mack.
Influence of sodium replacement on fluid ingestion following exercise-induced dehydration.
Intl J Spors Nutr 7:104-116, 1997.

When it comes to the sodium content of a sports drink - not too much, not too little is the key. Research indicates that certain amounts of sodium added to a flavored beverage will increase voluntary drinking and help prevent dehydration.

Introduction:
Inadequate drinking during strenuous activity can result in dehydration and impaired athletic performance. During intense physical activity, athletes often do not drink enough fluids to replace what they lose in exercise, resulting in what’s called “voluntary dehydration.” Because drinking the right amount of fluid during and after strenuous exercise is the front-line defense against dehydration, sports drinks should be properly formulated to encourage voluntary drinking.

According to research, additional sodium in sports beverages may encourage drinking and aid rehydration after activity.

Research Review:
Wemple et al. studied the effect of three different levels of sodium in a carbohydrate–electrolyte beverage (like a sports drink) on voluntary drinking and rehydration after intense physical activity. The sodium levels in the test beverages were 0, 575, and 1,150 mg/L.

What the Research Revealed:
• Small amounts of sodium added to a flavored, sweetened beverage increased drinking and improved fluid replacement following intense exercise.

• Fluid losses were replaced more quickly with the lower-sodium beverage than when using either the beverage without sodium or the high-sodium beverage.

• Surprisingly, the higher sodium level did not stimulate greater drinking, a finding the authors attributed to a rapid restoration of blood volume that decreased the desire to drink.

Research Result:
Proper amounts of sodium in sports drink can help enhance flavor and increase the amount of fluid dehydrated athletes will drink to replace fluid losses.