Heat exhaustion
Heat exhaustion is where the body loses its ability to cool down efficiently. Normally, the body cools itself by sweating. But if you are exposed to high temperatures for a long time and don't replace the fluids you lose, the body systems that regulate temperature become overwhelmed. The athlete’s skin will feel moist and clammy they will have a fast, weak pulse and shallow breathing, they may look pale and feel weak and dizzy.
Hyponatraemia
Hyponatraemia is a result of an overhydrating in the body. It can happen during activites where water is constantly drunk and there is excessive sweating. The effects are to dilute the blood salts, which is dangerous and results in lethargy, confusion and nausea.
Hypontremia often occurs during marathons, this is because water is being taken on board constantly whilst running at the same time that the water is being taken on sweating is also occurring.
Hypo-hydration
Hypo-hydration is when athletes dehydrate to meet the needs of competition, usually a competition that has a weight class, such as boxing and rowing.
Hyper-hydration
Hyper-hydration is also known as super hydration. Hyper-hydration involves drinking large amounts of water every day, creating a state in which the body is hyper-hydrated. This is good to carry out when in hot climates. Water on its own is not sufficient enough for hyper-hydration as it leads to greater urine output therefore water and glycerol are used to achieve the desired effects. Glycerol helps to get more water into cell fluids, which produces an overall increase in total body fluid.
Hyper-hydration is usually carried out for up to a week before completion, especially athletes that are acclimatising to new environments. Athletes take in 400-600ml of water an example of hyper-hydration will be athletes that are travelling to a different country that has higher climate conditions such as competitions as the world cup or Olympic games. Athletes need to hydrate themselves in preparation for competition to ensure they don’t become dehydrated.
Fluid Intake
Preventing dehydration – when preventing dehydration is it important to consider the environment. If you are in a very hot or humid climate, you'll find that your going to lose body fluid at a much faster rate and therefore, will need to be particularly careful to ensure you are taking in enough.
The other factor to consider when preventing dehydration is the intensity you are working at. The best way to avoid dehydration from happening is to try and consume eight to ten glasses of water during the day, to ensure that you are not starting at a deficit, and then to drink a small amount of fluid every 15 to 20 minutes while you are exercising.
A netballer needs to ensure she is fully hydrated before competition to prevent dehydration during the match. She should drink water before the match and take on a fluids during quarter breaks this will prevent dehydration.
Schedule training to cooler times – by scheduling training to cooler times will help to prevent dehydration, this is because the temperature is cooler therefore dehydration will take longer to set in.
Limit alcohol intake – Alcohol is a diuretic. Therefore it encourages the body to lose more water than it takes on by halting the production of the body's anti-diuretic hormone. This means you feel the need to pass urine excessively; this speeds up the loss of fluid from the body and leads to dehydration.
Aim to drink up to 3 glasses (600ml) of water before exercise – by drinking 600ml of water before exercise means your body is fully hydrated and therefore dehydration is less likely to occur.
Always carry water or diluted juice to sip or drink frequently – by carrying water or diluted juice means you always have a drink on you, this will prevent you from becoming dehydrated.
Drink before feeling thirsty – once you feel thirsty dehydration has already kicked in therefore to prevent dehydration you need to drink before you feel thirsty.
Sports Drinks
Isotonic - these types of drinks are taken before and during exercise for rapid absorption and to meet fluid and carbohydrate requirements with carbohydrate requirements being 130g. Isotonic drinks are good for endurance activities. Isotonic drinks are good for sports people such a footballers, netballers and rugby players.
Hypertonic – these drinks are taken after exercise and they have low levels of water and contain high sugar levels (>8g CHO per 100ml). They begin the hydration process whilst simultaneously helping to replenish carbohydrate energy reserves. Hypertonic drinks are good for athletes that need to replace fluid lose.
Hypotonic – these are taken before exercise and have little carbohydrates and are quick to replace fluids (<4g CHO per 100ml). They are best used later in the recovery process to boost energy intake while still encouraging fluid uptake during the final stages of hydration. Long distance runners that will be loosing or have lost a lot of fluids should take on hypotonic drinks.