It is impossible for young athletes children (and adults!) to perform at their best when they are dehydrated. Even small degrees of dehydration can cause a drop in performance and make them feel unwell. If the warning signs of dehydration are ignored, youngsters can overheat rapidly and develop more severe symptoms that could result in heat-related illness. This article explains the dangers of dehydration, what symptoms you should be looking out for and how to prevent young athletes becoming dehydrated during exercise. It also provides guidance on the amount and timing of drinking around exercise, and which types of drinks to encourage young athletes to choose during training.
How much should young athletes drink each day?
There are no official guidelines for fluid intake, although many health professionals advise drinking 1 ½ litres per day as a general guide. The European Food Safety Authority (EFSA) recommends children aged 9 – 13 years drink 1.3 – 1.5 litres daily; those over 14 years between 1.4 and 1.8 litres.
These recommendations don’t take account of exercise. Young athletes will lose extra fluid through sweating during training, more in hot and humid conditions, and will certainly need to drink more than non-active people. They should drink little and often throughout the day, and must not ignore thirst, no matter how busy they are.
What are the signs of dehydration?
Young athletes are much more susceptible to dehydration and overheating during exercise than adults for the following reasons:
- They sweat less than adults (sweat help keep the body’s temperature stable)
- They get hotter during exercise
- They have a greater surface area for their body weight
- They often fail to recognise or respond to feelings of thirst
By the time children are thirsty they will already have lost quite a bit of fluid and may already be dehydrated. Apart from increased body temperature there are other warning signs of dehydration include:
- Exercise feels much harder
- Unusually lacking in energy
- Feeling very hot
- May develop cramps, headaches and nausea
- Concentration is reduced
- Ability to perform sports skills drops
- Fatigue sooner and loses stamina
More severe symptoms include dizziness, vomiting, disorientation and increasing weakness. Eventually this can lead to exhaustion, heat stroke and, in some cases, can be fatal. Even mild dehydration – a 2% loss in body weight – can impair performance, reduce stamina and strength, and increase fatigue.
What’s the best way of preventing dehydration?
Prevention is better than cure. It’s important that young athletes are fully hydrated before they start training. If they are not fully hydrated before exercise, then they risk becoming more dehydrated during the training session and suffering early fatigue, headaches, nausea and dizziness.
If they train in the evening, make sure they drink plenty of water during the day. If they train early in the morning, they should have a drink as soon as they get up. They will know if they are properly hydrated from the colour of their urine. It should be pale straw-coloured, not deep yellow, and should not have a strong odour. Try to get them into the habit of self-monitoring their hydration status.
Encourage young athletes to make up for any previously incurred fluid deficits by consuming 400 – 600 ml about two hours before training or competition and to continue drinking little and often during the warm up.
When it comes to choosing the best drink, water is one of the best ways of hydrating the body. It is rapidly absorbed – and free too. It is a perfectly good pre-exercise choice together with a pre-exercise meal or snack (see ‘Nutrition for Young Athletes’).
How much should they drink during training?
Children can easily forget to drink during training, oblivious to thirst as they focus on beating their friends or just having fun training.
Encourage young athletes to start drinking early during their training session – certainly within the first 30 minutes – and to continue drinking at regular intervals. They should not wait until they feel thirsty or experience symptoms of dehydration before they start drinking. For most youngsters, thirst is not a reliable guide to fluid losses. They may be dehydrated by the time they feel thirsty.
As a rule of thumb, they should aim to drink around 500 ml per hour – more in hot humid weather or when exercising very strenuously. If they exercise for a shorter time or at a lower intensity, they can drink proportionally less as the risk of dehydration would be smaller. Encourage them to drink little and often during training, ideally every 15 – 20 minutes or whenever there is an appropriate break. Make sure they have a water bottle (or two for longer sessions) and keep it within easy reach throughout training.
To get a more accurate idea of their fluid losses, young athletes can weigh themselves before and after training. The American College of Sports Medicine recommends that athletes should lose no more than 2% of their body weight during exercise. This equates to 1.2kg for a 60kg person. Each 1 kg of weight loss is equivalent to 1 litre of fluid. They should try to drink at least half of this amount during training, the rest afterwards.
What should young athletes drink during training?
Sports drinks or energy drinks are not necessary for activities lasting less than 60 – 90 minutes. Water will replace fluid and prevent dehydration; no extra fuel should be necessary. But many children are not very keen on drinking water so they may not drink enough. In these cases, sugar-free squash may be an option. The most important thing is that children drink enough and don’t become dehydrated. Therefore, the taste is important. If they don’t like it, they won’t drink it! Water tends to quench one’s thirst even if the body s still dehydrated.
For training sessions lasting longer than an hour, or perhaps for very intense sessions lasting 30 – 60 minutes, a drink that provides carbohydrate (such as squash, diluted fruit juice or sports drinks) is a better option than plain water as it provides extra fuel for the muscles. The sugars also help the fluid in the drink get absorbed more quickly (provided it is at a dilution of between 4 and 8g carbohydrate per 100ml).
Can commercial sports drinks help young athletes perform better?
Sports drinks are essentially sugar, water and electrolytes (namely sodium). They contain between 6 and 8g sugars/ 100ml (60 – 80g/ litre), which is a little lower than other soft drinks, such as cola, which typically contain 9 – 12g per 100 ml (90 – 120g/ litre). At this concentration, the sugars promote speedier water absorption compared with drinking plain water. At higher concentrations, the sugars actually slow down water absorption into the body, which is why ordinary soft drinks would be unsuitable for rehydration during exercise. The electrolyte, sodium, in sports drinks stimulates thirst and also helps the body retain the fluid consumed.
Many studies have shown that consuming sports drinks instead of water during exercise lasting more than an hour can help improve performance. This is due mainly to their sugar content, which helps maintain blood sugar levels and fuel the muscles. However, the major drawback of commercial sports drinks is their cost. For young athletes training daily and therefore requiring 500ml – 1 litre per session, the high price of these drinks is difficult to justify.
For a less expensive sports drink, mix fruit juice 50/50 with water; dilute 1 part squash or cordial with four parts water; or dissolve 40 – 60g sugar in 1 litre of water. You may add a pinch of salt (0.5 – 1g per 1 litre), although this is not essential for most types of training. These ‘home-made’ versions of sports drinks will help athletes exercise longer and improve performance during exercise longer than an hour.
What to drink during training
For exercise lasting less than an hour:
For exercise lasting more than an hour:
- Fruit juice diluted with an equal amount of water
- Squash diluted 1:6 with water
- Sugar dissolved in water (40 – 80g per 1 litre)
- Commercial sports drink
What is the best way to rehydrate after training?
After training, the number one priority is to replenish fluid losses. So encourage young athletes to have a drink straight away — water, squash or diluted fruit juice are the best options.
The International Olympic Committee recommends drinking 1.2 – 1.5 times the weight of fluid lost during exercise. This is to compensate for the increased urine production that accompanies drinking large volumes of fluid. If athletes weigh themselves before and after training, they can work out how much fluid they have lost. For each 1 kg of weight loss, they need to drink 1.2 – 1.5 litres. This should be drunk in divided amounts over an hour or so, not in one go.
Milk, flavoured milk and milkshakes are also good options for recovery drinks. Studies at Loughborough University suggest that low fat milk-based drinks are just as effective as commercial sports drinks in helping athletes recover and rehydrate. They have the advantage of additional nutrients not found in sports drinks; and are therefore good for promoting muscle recovery.