Sports drinks: the real facts
There are many electrolyte sports drinks currently on the market. It can become confusing amongst all the marketing and hype to know which sports drinks are the best, what you should be looking for when choosing the right sports drink, and when and why you should use one.
Why use electrolyte drinks?
Electrolyte drinks assist with rapid replacement of fluid and electrolytes lost during exercise training or hard physical labour. They help with muscle recovery and soreness, preventing dehydration, and providing stamina and increased endurance during strenuous exercise.
Electrolyte drinks ingested during exercise aims at providing a source of carbohydrate fuel to supplement the body's limited stores and supplying water and electrolytes to replace losses incurred through sweating.
Symptoms of dehydration
Symptoms of dehydration include muscle weakness, dizziness, headaches, fatigue, cramps, and thirst. Dehydration greatly affects athletic performance. As the body loses water its core temperature rises. This affects metabolic pathways, interferes with cardiovascular functioning, and reduces total exercise capacity. You should not rely solely on your thirst response as you can enter a state of dehydration and not feel the sensation of thirst for several hours.
Electrolyte drinks should be used during and after training for fluid and electrolyte replacement. The athlete must begin exercise fully hydrated and regular ingestion of fluids is beneficial where the exercise duration exceeds 40 minutes1. Failure to properly rehydrate after a training session increases the likelihood of waking up the next morning still dehydrated. This will reduce your training potential during the subsequent day and leads to a cycle of accumulating dehydration.
What do electrolytes do?
Electrolytes important for the functioning of many vital processes in the body include magnesium, calcium, potassium, sodium, chloride and phosphate. Electrolytes regulate the fluid balance between body compartments: they help to maintain an acid-alkaline balance required for normal cellular activities, and carry electrical currents which facilitate the control of hormone and neurotransmitter secretion necessary for nerve and muscle function. Electrolytes are also needed as cofactors for enzymes which influence a number of functions in the body including digestion.
Exercise is associated with increased magnesium excretion from the body through sweating. Magnesium is needed for oxygen delivery to working muscles during training2. Magnesium depletion may reduce physical performance and reduce exercise capacity.
Sodium and potassium are necessary for correct functioning of nervous and muscle tissue and the flow of fluid in and out of cells. Besides contributing to hardness of bones and teeth, calcium plays an important role in blood clotting, neurotransmitter release, maintenance of muscle tone and excitability of nervous and muscle tissue.
Choosing the right electrolyte drink
Sports drinks must contain a balanced ratio of carbohydrates to provide rapid energy, fluid and temperature control. Carbohydrates and electrolytes enhance the body's uptake of water. During exercise, the ingestion of water, in association with carbohydrate and minerals, is effective in attenuating both fatigue and illness due to dehydration3.
Choose an electrolyte drink not too high in sugar as this can cause gastrointestinal discomfort and dehydration. Many sports drinks on the market today contain extremely high levels of sugars equal to that of soft drinks. If you are not partaking in regular high intensity exercise, drinking these sugary sports drinks will promote weight gain. Electrolyte drinks are needed when you are exercising for more than 40 minutes, playing sport (football, soccer etc) or if your work involves hard physical labour. These drinks are also very useful when you are sick with diarrhoea (ie, to prevent dehydration).