Frequently asked questions
Q1. There are several sports drinks on the market. What is the difference between them?
Q2. Is water better than a lightly diluted sports drink for rehydrating?
Q3. Should I take added salt to ensure that what I lose in sweating is replaced?
Q4. Can I combine fluid and fuel replacement after exercise?
Q5. What are 'high-glycaemix index' foods?
Q6. Will pre-training snacks make me sick during training?
Q1. There are several sports drinks on the market. What is the difference between them?
Essentially there are 3 main types of sports drinks.
1) The Sports drink (isotonic)
2) The Energy drink
3) The Recovery drink
The difference between both the Sports and Energy drink is mainly in the concentration of carbohydrate in the different drinks. The Sports drink is lightly diluted and may range between 4 and 8 percent sugar or carbohydrate concentration. They generally contain electrolytes such as sodium and potassium. The sodium especially aids in rehydrating. This means that they are suitable for fast entry into the blood stream. In fact the lighter the concentration of the sugar in the drink the faster the uptake into the bloodstream.
Drinks that are more concentrated (above 8%) are generally regarded as 'Energy' drinks. Their main goal is to provide energy as opposed to speedy delivery of energy and rehydration. 'Energy' drinks thus may delay the time it takes carbohydrates to enter the blood stream and so are not considered ideal rehydration drinks (2,5,6,17).
Recovery drinks are ideal after training or playing. They combine both protein and carbohydrate and are intended to restore lost fuel and also to start the muscle repair process so that the player can recover faster.
Q2. Is water better than a lightly diluted sports drink for rehydrating?
Interestingly, there is good evidence to recommend taking sports drinks instead of water if the goal is speedy rehydration (17,33,48,53). The lightly diluted sports drinks (approximately 6%) tend to be better drinks at ensuring fluids are delivered into the system quicker than water. In addition, drinks that contain approximately 50 mmols of sodium per litre are optimal for fluid retention (33). So check that your sports drink has a concentration of approximately 6% carbohydrate with a sodium content of approx 50 mmol/litre when rehydration is the goal.
Q3. Should I take added salt to ensure that what I lose in sweating is replaced?
There is good evidence to recommend the addition of some salt to a rehydration drink (2,7,26,53). As a result, most sport drink companies have now recognized the optimal level necessary to ensure fast absorption of the drink. Taking additional salt is therefore not necessary. However, when taking water as the rehydration drink it may be useful to consume some lightly salted snacks (such as salted crackers or lightly salted sandwiches) in conjunction with water. This may be effective in assisting rehydration and any additional carbohydrates consumed are helpful in restoring muscle fuel. There is no real need to add any further salt as generally all salt requirements are met by the intake of food.
Q4. Can I combine fluid and fuel replacement after exercise?
The immediate post-exercise period is the best period in which to replenish muscle fuel - called glycogen. Typically after a hard training session or game your muscle fuel stores will be significantly reduced. The type of fuel lost is muscle sugar or more correctly muscle glycogen. Consuming both fluid and fuel in the immediate post-exercise period is highly recommended. Consuming high-glycaemix index carbohydrates immediately after training in conjunction with some protein is ideal.
Q5. What are 'high-glycaemix index' foods?
The Glycaemix Index (GI) is an index of the speed at which carbohydrates enter the blood stream. Foods with higher GI values produce a faster rise in blood sugar or glucose than foods with a lower value. Sugar or more specifically glucose enters the blood stream the fastest. It has a GI index of 100. Other foods are then ranked relative to this. For example, cornflakes have a value of 80 indicating that they enter the blood stream relatively quickly. Oatmeal or porridge by contrast has a value of 49 and it is thus much slower in its entry into the blood stream. In general it is considered better to have a slow and steady rise in blood glucose as opposed to a fast sudden rise when not exercising. Therefore foods with a GI lower than 75 are recommended for regular consumption during the day. The exception to this for the player is the immediate post-exercise period when the body, in particular the liver and muscle fuel stores, requires fast replenishment of lost fuel.
Q6. Will pre-training snacks make me sick during training?
Most players will have no problem in a subsequent bout or session when they have a pre-training snack about 2 hours before training. Some players can easily cope with food in their stomach from snacking one hour before training. Indeed all players should train themselves to be able to eat a pre-exercise snack as outlined above in the snack section before training. This then allows them to be well fuelled for the session and also prepares them to be comfortable with any pre-game snack that they ingest on the day of a game. However, there are players who will feel a little nauseated if they consume solid fuel or beverages in the period before training or playing. Such players should experiment with either sports drinks or easily digested solid carbohydrates (e.g biscuits with tea or sports drinks) before training and try to identify a solid fuel or beverage that suits them. NB Don't leave it to the day of the game to experiment.
