How Does A Sports Beverage Affect Urine Output If Consumed Before Exercise?

It is well known that hydration is crucial to athletic performance as well as safety. In most circumstances, fluid intake is the mode of entry into your body, while breathing, sweat loss and urination make up the majority of fluid loss. Fluid loss begins at the start of exercise and lasts up to four hours following an exercise session. The use of sports beverages may be one way to influence the volume of urine produced during your exercise.

Staying Hydrated

The amount of fluid loss depends on your genetics, muscle mass and exercise duration, as well as the ambient temperature and humidity. Always begin athletic activities well hydrated. In general, consume 10 to 20 ounces two hours before, 10 to 15 ounces 20 minutes before, and 4 to 8 ounces every 20 minutes during exercise. Take a bathroom break before exercising.

Reduced Urine During Exercise

Urine is your body’s way to remove wastes and control extracellular to intracellular fluid balance. It contains urea, chloride, sodium, potassium, creatine and toxins. During exercise, urine production is reduced by the body’s ability to conserve fluid for thermoregulation, or sweating. However, it is possible to over-consume fluids and result in the need to void during exercise.

Electrolytes, Glycerol and Urine Output

Typically, sports beverages are categorized into pre-exercise, exercise and recovery drinks. Pre-exercise and exercise formulas usually contain sodium, potassium and carbohydrates.
Sodium and potassium are responsible for maintaining extracellular and intracellular fluid volume, which is achieved by concentrating sodium outside but potassium inside the cell. If extracellular sodium level becomes too low -- mainly through sweat loss -- the body will excrete water to maintain its concentration. In a study published in the July 2008 issue of "European Journal of Applied Physiology," for exercise lasting more than 60 minutes, sports drinks containing sodium improve hydration by reducing urine volume.
Some sports drinks contain glycerol, a carbohydrate derivative with the ability to hold onto water. In 2008, a group of British researchers examined the effects of glycerol in hydration. According to their findings, published in the September 2008 issue of "Journal of Strength and Conditioning Research," the consumption of fluid with glycerol resulted in significantly higher retention in athletes compared to the same volume consumed without glycerol. However, be cautious that glycerol-induced “hyperhydration” is considered a violation for some sports. People with hypertensive tendency and pregnant women should avoid glycerol-hydration, which increases blood volume.

Timing is Everything

While is it important to stay hydrated throughout your exercise, it is undesirable to need multiple bathroom breaks. Sports beverages that provide sodium and glycerol may reduce urine output by enhancing the body’s ability to retain fluid. However, little scientific data exists that distinguishes between the effects of consumption before and during exercise on urine output. Consuming it solely before exercise is unlikely to yield measurable reduction since respiratory and sweat loss vary greatly depending on environmental factors. Experiment with the amount and timing to personalize for best results. When in doubt regarding your hydration and urine output, check with your health care providers or consult a sports dietitian.