Hydrating when playing team sports can be difficult as some have rules which only allow fluid consumption at particular times. Unless sweat rates are relatively low, it is generally inevitable that some degree of dehydration will be incurred during team sports - the goal is to minimise the degree of loss. Therefore, you must take every possible opportunity to hydrate! Skills and fitness can be better developed in the training environment when well hydrated, which will impact on game day performance. Likewise, match performance will be optimised1.
How to hydrate in training sessions and games
Fluid loss during exercise is very specific to the environmental, physical and clothing demands of sport, and there is also a large individual variation in sweat rates. The environmental factors include temperature, relative humidity, sunshine, and wind, while physical factors include gender, position on the field and the type of sport demands, length of game, size of athletes and perhaps also level of competition.
Most research in this area has been done on soccer players. For example, reported sweat rates of elite males in winter competitions range from 710-1770ml/hr2, whilst in summer it is from 990-2090 ml/hr3,4. In reality, this difference is not great considering the changes in environmental conditions, which may be due to more clothing being worn in winter months. For younger or less elite players, sweat rates may be lower4. In other football codes, such as rugby league and union, sweat rates could be even higher due to larger sizes of the players (there have been reports of sweat rates up to 3.0 L/hr in AFL players). Female soccer players tend to have slightly lower average sweat rates in training as a group than males (around 800 ml/hr in summer), most likely due to their smaller body sizes4. Field sport players have consistently been reported to replace, on average, less than 50% of their fluid losses during training or competition3,4,5. See the section 'How to Determine Your Sweat rate' to help establish your average sweat rate, to help you devise your fluid replacement plans. Alternatively, a qualified sports dietitian can guide you through this process.
What fluids should be consumed?
Most importantly, the drink of choice should be one that you enjoy the flavour of during exercise. Studies have shown that flavoured drinks tend to be consumed more than unflavoured ones6. We also know that some sodium (salt) in your fluid increases the retention of the fluid consumed compared to water, and when fluid intakes may not match losses it's extremely important to utilise all of what's consumed as effectively as possible. Considering the duration of many team sports, carbohydrate is also an important consideration for maintaining muscle fuel supplies all the way through. Hence, consuming a sports drink such as POWERADE ION4 has the combined advantages of fluid, taste, sodium and carbohydrate all in a neat package. One word of caution, never wash your mouthguard out with a sports drink or beverage other than water so you do not damage your tooth enamel.
What about the temperature of the fluid?
For maximal absorption from the stomach, the optimal temperature of a fluid is "cool" - around 15°C. However, there is recent evidence that consuming cooler drinks (4-10°C) can help reduce the body's temperature7,8, as well as increasing the total amount of fluid consumed in hot conditions8, which is beneficial when playing in the heat.
Use training sessions to practice drinking more and to understand your tolerance to fluid during exercise. You can train yourself to drink more.
Always take plenty of fluid to training sessions and to games - it's better to have more than not enough.
Take advantage of every opportunity during a game to take a drink.
At half time, drink as much as you can tolerate (generally at least 400mL). Try to drink most of this at the start of the break, to allow for maximum time for the fluid to be absorbed.
Swallow the drink rather than rinsing your mouth and spitting it out.
Whilst pouring cool water over your head may make you feel better in the short term, actually ingesting it will help more over the longer term!
Rehydrate effectively after the game / training session by consuming 150% of the fluid lost within the next couple of hours (see the section on "How can POWERADE help me after sport?").