Recommended Fluid Intake
The need for players to adequately hydrate themselves prior to activity, whether that is training or competition, is well documented and as a result players are generally good at carrying this out. However, the requirement to continually stay hydrated during activity is a task that is very rarely effectively fulfilled and as a result players are performing with insufficiently hydrated bodies.
It is suggested that prior to activity the individual should consume between 400 and 600ml of fluid, ideally not just plain water but sports drinks or fluids containing a small amount of salt. As this can aid with the retention of the fluid and reduce the rate and amount that passes straight through the body and is excreted in urine. It is advised that this fluid is sipped as opposed to gulped down and that time is allowed for the excess water to be excreted from the body.
Sweat is the main reason fluid is lost during activity. Sweating is the bodies way to ensure its temperature is kept at the desired level (37-38°C) once the other common heat removal methods (such as convection, conduction and radiation) are overloaded and exhausted. There are many factors which can affect the amount of sweat the body produces. Some of the more obvious factors include:
Climate temperature – a 15°C change in temperature can alter the sweat produced by up to 1.5 litres (although this figure can alter if the body has become used to performing in such a climate). Such a climate change can occur across continents and even individual countries.
Humidity levels – If there is moisture in the air then the amount evaporated off the body is decreased.
Clothing – Amount and type of clothing has a direct influence on the quantity of sweat produced.
Intensity and Duration of the exercise – The longer and harder the individual works for, the more sweat is produced.
Due to the amount of fluid lost during exercise, it is suggested that fluid is replaced every 15 minutes, although this figure can vary depending on the influence the above factors have on training or competition. Otherwise the participant may experience dehydration. If the body becomes dehydrated then many of its systems can suffer. Such problems that can arise through dehydration include;
- Work rate and effort perception.
- Thermal regulation.
- Lactate production within the muscles.
- As well as reduced functions of the excretion and digestive systems.
It is therefore crucial that players are continually re-hydrating themselves to ensure none of the above factors can influence their performance. So what is the correct amount of fluid that should be taken on board to ensure hydration? The guidelines at present for the average footballer are as follows;
- 400-600 ml of fluid approximately 3 hours before activity (if the intensity is known to be high then adjust intake accordingly).
- 150-250 ml approximately 15 minutes before commencing (just sipping).
- 150-250 ml every 15 minutes during activity (depending on environmental and intensity factors).
- 1.5 litres for every 1 kg of body weight lost after activity.
Due to the nature of soccer matches there does not presently exist a chance to take water on board during the halves at designated periods, as no time outs or water breaks exist. Therefore the following should be followed to delay the onset of dehydration;
- 400-600 ml immediately before kick off.
- 400-600 ml during half time (once again only sipped).
- 1.5 litres for every kilogram of body weight lost at full-time.
Players should also take any chances during games to get fluid inside them. For example when there is an injury or a break in the play for any other reason.
There are three main ways to test and assess a player’s hydration level after they perform. The first simple test is to measure their body weight before and after activity, any difference will be the amount of fluid lost. A second process is to check the colour of the player’s urine. A dark colour means the individual is de-hydrated, while a clearer lighter colour means that their body is adequately hydrated. One final approach is to use a Osmocheck™ device which can instantly provide an accurate reading of an individuals hydration levels.
This article has focused on hydration in players when they are performing in either training sessions or matches, with a very adult orientated approach. However it is the younger generation that require the most attention and educating with regards to hydration as their under developed bodies are not capable of the same thermal regulation as adults. Children should therefore be encouraged to consume fluid on a more regular basis (every 10 minutes) and be provided with enough fluid to not just meet their thirst requirements but exceed them.
So to ensure the players under your supervision maintain a healthy and hydrated physical well-being you as the coach should ensure they all have access to the sufficient amount of fluids and are allocated the time to take those fluids on board.