Fitness Goop

Electrolytes and Proper Hydration for Exercise

Optimum nutritional habits are essential during your physical fitness training or exercise. Fundamental components include hydration status, carbohydrate and protein intake as well as electrolyte repletion, and joint health.

Drinking plenty of water before during and after your training (especially during summer months) will prevent dehydration as well as overheating, both of which may lead to nausea and lightheadedness. In fact, heat production during physical activity often strains the body’s own heat dissipating mechanisms, especially in high temperatures. As such, it is recommended to drink about 150-200 milliliters every 15 minutes during your training but take into consideration the daily temperature and intensity of your exercise regimen.  

While hydration in the form of pure water is key, re-hydration in the form of an electrolyte repletion formula or sports drink cannot be emphasized enough. According to Dr. Edmund Burke, PhD. in exercise physiology and past Director of Exercise Science Program at the University of Colorado, the following factors are essential to facilitate muscle recovery post-exercise.  

First, restore electrolytes and water (essential electrolytes being sodium, potassium, magnesium). Electrolyte repletion in the form of a sports re-hydration drink with minerals mentioned above not only promote post-exercise recovery, but a drink that includes ingredients such as citric acid and malic acid are also necessary for energy production. 

Prolonged exercise (especially in the heat) can contribute to sweat loss and depletion of about 13-17grams of salt per day, approximately 8grams more than what is consumed on an average day (McArdle WD, Katch FI et al., 2006). Studies have shown that plasma volume is more rapidly and completely restored in the post-exercise period if some sodium chloride (approximately 225mg per 500 mL of fluid) is added to the water consumed. This sodium concentration is similar to the upper limit of the sodium concentration found in sweat (Gleeson M, 1997). Potassium, present in intracellular fluid, is responsible for regulating total body water and stabilizing controlled and automatic muscle contractions. In a study of athletes running 40 minutes at 70 degrees Fahrenheit, potassium loss through sweat was estimated at 435 mg/hour (Wenk C, et al., 1993). Other studies have also found that supplementing with potassium during training increase markers of recovery, primarily serum lactate and muscle hydration (Tarnopolsky MA, et al., 1996).   

Secondly, replenish glycogen stores rapidly via insulin, which not only supports glycogen synthesis, but also protein rebuilding. Essentially, intake of carbohydrates with a high glycemic index within two hours post exercise is fundamental to optimize recovery, specifically aiming for a 4:1 carbohydrate to protein ratio to optimize glycogen replenishment and enhances aerobic endurance performance by 24%. Indeed, studies show that endurance athletes who drink 6-8g of carbohydrates per 100 ml of fluid, including electrolytes (sodium, potassium, magnesium and chloride) are able to delay exhaustion when compared to those drinking only water (Coggan, 1991; Yaspelkis, 1993) 

Contrary to the popular belief that intake of a protein shake is best taken after exercise, studies show that too much protein (and fats) post-exercise actually slows re-hydration and glycogen replenishment. Furthermore, a higher protein to carbohydrate ratio slows gastric emptying which compromises an increase in insulin levels, ultimately impeding the storage of glucose into glycogen within muscle tissues. That said, a balance of protein to carbohydrate in the ratio outlined above is also necessary as too little protein also fails to facilitate protein’s ability to increase insulin levels. Secondary to that, protein provides a source of energy, but also stimulates muscle tissue repair and reduces muscle soreness.

While intake of electrolytes for optimal physical performance continue to be studied, not much has been done to address the effects of temperature in the liquid that is being ingested, on athletes’ performance. A 2006 study published in the Journal of Experimental Physiology examined the relationship between the intake of fluids at different temperatures, and its effects on endurance capacity in a hot environment (Mundel, T., King J. et al.). The authors found that 75% of the study subjects had approximately 11% improved endurance capacity (drinking a cold beverage at 4 degrees Celsius) before reaching exhaustion when compared to the group that drank warm liquid (19 degrees Celsius). Since fluid ingestion during exercise is known to minimize hyperthermia, it appears logical that a cold drink during exercise may lessen increase in core temperature and thereby improve overall performance. 

The take-home message is that during your work-outs, ensuring hydration with plenty of water and a sports re-hydration drink will prevent dehydration and increase your stamina while improving your recovery time, enhance your performance overall and replete necessary minerals lost in sweat.

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