Hydration and Fluid Replacement By Michael Bransfield

Hydration and Fluid Replacement Fluid in take is the most important nutritional factor during competition . Dehydration is a concern during any physical activity. Athletes should aim to drink regularly rather then wait until they become thirsty as thirst is often a poor indicator of hydration. Fluid requirements vary remarkably between athletes and between exercise situations. Fluid losses and the onset of dehydration are affected by: Genetics - some people innately sweat more than others Body Size - larger athletes tend to sweat more than smaller athletes Fitness - fitter people sweat earlier in exercise and in larger volumes Environment - sweat losses are higher in hot, humid conditions Exercise Intensity - sweat losses increase as exercise intensity increases Generally athletes should aim to drink 150- 250mls of water every 15 minutes

Fluid in take is the most important nutritional factor during competition . Dehydration is a concern during any physical activity. Athletes should aim to drink regularly rather then wait until they become thirsty as thirst is often a poor indicator of hydration.

Fluid requirements vary remarkably between athletes and between exercise situations. Fluid losses and the onset of dehydration are affected by:

Genetics - some people innately sweat more than others

Body Size - larger athletes tend to sweat more than smaller athletes

Fitness - fitter people sweat earlier in exercise and in larger volumes

Environment - sweat losses are higher in hot, humid conditions

Exercise Intensity - sweat losses increase as exercise intensity increases

Generally athletes should aim to drink 150- 250mls of water every 15 minutes

Fluid Losses From the pictures above it can be seen that in normal everyday conditions water input vs. output is balanced. However during heavy exercise the amount of fluid lost as sweat increases greatly meaning that a larger quantity or fluid most be consumed to recreate a balance. www.extension.iastate.edu/nutrition/sport/images/02.011A.jpg&imgrefur

General Fluid Replacement Guidelines Immediately, before exercise commences, consume 200-600 ml of fluid. Develop a plan for fluid intake for all exercise sessions longer than 30 minutes. Aim to match previous fluid losses as closely as possible (within 1% of body mass). Take into account all the opportunities within the sport. Begin drinking early in the exercise session and continue to drink small amounts regularly. Sports drink or water are the best options. Aim to replace fluids as they are lost ( http://www.ausport.gov.au/ais/nutrition/factsheets/hydration2/fluid_-_who_needs_it )

Immediately, before exercise commences, consume 200-600 ml of fluid.

Develop a plan for fluid intake for all exercise sessions longer than 30 minutes. Aim to match previous fluid losses as closely as possible (within 1% of body mass). Take into account all the opportunities within the sport.

Begin drinking early in the exercise session and continue to drink small amounts regularly. Sports drink or water are the best options.

Aim to replace fluids as they are lost

( http://www.ausport.gov.au/ais/nutrition/factsheets/hydration2/fluid_-_who_needs_it )

General Fluid Replacement Guidelines cont. Drink plenty of water after exercise, past the point of quenching your thirst Avoid drinking tea, coffee, cola drinks and alcohol after training or games Glucose are not recommended as they can speed up the onset of dehydration Sports drinks should only be taken in small amounts before a sport to prevent the early use of glycogen stores

Drink plenty of water after exercise, past the point of quenching your thirst

Avoid drinking tea, coffee, cola drinks and alcohol after training or games

Glucose are not recommended as they can speed up the onset of dehydration

Sports drinks should only be taken in small amounts before a sport to prevent the early use of glycogen stores

In events of less then 30 mins Hydrate well before the event Fluid taken during the event will not benefit performance as it will not become available to the body within 30 minutes Fluid taken during the event will alleviate a dry mouth and improve perceived exertion

Hydrate well before the event

Fluid taken during the event will not benefit performance as it will not become available to the body within 30 minutes

Fluid taken during the event will alleviate a dry mouth and improve perceived exertion

In events of 30- 60 mins Begin the event well hydrated As a general rule replace fluid every 15 minutes by drinking 150- 250mls of water A supplementary source of carbohydrate during exercise has been shown to improve performance in some events as short as 60 minutes. A general recommendation is 30- 60 grams of carbohydrate per hour. The average sports drink contains 60- 80 grams per liter so an athlete should use a diluted sports drink approximately one third sports drink and two parts water

Begin the event well hydrated

As a general rule replace fluid every 15 minutes by drinking 150- 250mls of water

A supplementary source of carbohydrate during exercise has been shown to improve performance in some events as short as 60 minutes. A general recommendation is 30- 60 grams of carbohydrate per hour. The average sports drink contains 60- 80 grams per liter so an athlete should use a diluted sports drink approximately one third sports drink and two parts water

In endurance events Begin the event well hydrated Replace fluid regularly Consume 30- 60grams of carbohydrate per hour of exercise, these carbohydrates can be obtained from sports drinks. Avoid carbohydrates that delay the stomach emptying(e.g. carbohydrate foods that are high in fat or fibre), or cause gastrointestinal problems. Good sources of carbohydrate are jam sandwiches, bananas, thick sugary syrups, muesli bars, jelly beans, cordial or other sports drinks

Begin the event well hydrated

Replace fluid regularly

Consume 30- 60grams of carbohydrate per hour of exercise, these carbohydrates can be obtained from sports drinks.

Avoid carbohydrates that delay the stomach emptying(e.g. carbohydrate foods that are high in fat or fibre), or cause gastrointestinal problems. Good sources of carbohydrate are jam sandwiches, bananas, thick sugary syrups, muesli bars, jelly beans, cordial or other sports drinks

Dehydration It has been demonstrated that dehydration of just 1-2% of body weight can alter physiological function and negatively influence an athlete’s performance. The signs of dehydration start just one hour or sooner of exercise. It is a risk factor for athletes developing heat cramps, heat exhaustion, and the potentially life-threatening heat stroke Dehydration can be prevented by drinking fluids regularly Signs and symptoms of dehydration include: Thirst Irritability Cramps Headache Nausea Vomiting Weakness Head or neck heat sensations Dizziness Decreased performance ( http://www.csmfoundation.org/James_Madison_Univ. Fluid_Replacement_Guidelines_and_Exertional_Heat_Illnesses.doc )

It has been demonstrated that dehydration of just 1-2% of body weight can alter physiological function and negatively influence an athlete’s performance. The signs of dehydration start just one hour or sooner of exercise. It is a risk factor for athletes developing heat cramps, heat exhaustion, and the potentially life-threatening heat stroke

Dehydration can be prevented by drinking fluids regularly

Signs and symptoms of dehydration include:

Thirst

Irritability

Cramps

Headache

Nausea

Vomiting

Weakness

Head or neck heat sensations

Dizziness

Decreased performance

( http://www.csmfoundation.org/James_Madison_Univ. Fluid_Replacement_Guidelines_and_Exertional_Heat_Illnesses.doc )

Sports Drinks Sports drinks are an ideal fluid to consume during and after training and competition sessions, allowing the athlete to replace fluid and electrolyte losses, and simultaneously providing an additional source of carbohydrate fuel. In many situations, sports drinks are a better choice than water because: They are likely to promote better fluid intake than water. They provide an additional source of fuel that may enhance performance and reduce immune stresses. In situations in which these benefits do not occur, sports drinks do not detract from performance compared to water. Powdered sports drinks can be made up in different concentrations to change the relative delivery of fluid and carbohydrate. For example, a more concentrated drink may be useful when intake of fuel has priority over hydration (e.g. exercise in a cold environment when sweat losses are small), and a more dilute drink may be useful when fluid replacement is critical.. Alterations to the standard formulation will change the taste profile and may reduce voluntary intake of the sports drink. http://www.ausport.gov.au/ais/nutrition/supplements/resources/supplement_fact_sheets/sports_drinks

Sports drinks are an ideal fluid to consume during and after training and competition sessions, allowing the athlete to replace fluid and electrolyte losses, and simultaneously providing an additional source of carbohydrate fuel. In many situations, sports drinks are a better choice than water because:

They are likely to promote better fluid intake than water.

They provide an additional source of fuel that may enhance performance and reduce immune stresses.

In situations in which these benefits do not occur, sports drinks do not detract from performance compared to water.

Powdered sports drinks can be made up in different concentrations to change the relative delivery of fluid and carbohydrate. For example, a more concentrated drink may be useful when intake of fuel has priority over hydration (e.g. exercise in a cold environment when sweat losses are small), and a more dilute drink may be useful when fluid replacement is critical.. Alterations to the standard formulation will change the taste profile and may reduce voluntary intake of the sports drink.

http://www.ausport.gov.au/ais/nutrition/supplements/resources/supplement_fact_sheets/sports_drinks

Answers Q1. Dehydration which is affected by genetics, body size, fitness, environment and exercise intensity. Q2. Replace fluid as they are lost, drink plenty after exercise past point of quenching thirst, 200- 600mls before exercise commences Q3. Because it does not become available to the body in that amount of time Q4. Replace fluid every 15 minutes by drinking 150- 250mls of water during event Q5. Fluid loss greater then 1% - 2% of total body weight, Thirst Irritability, Cramps, Headache, Nausea, Vomiting, Weakness, Head or neck heat sensations, Dizziness and Decreased performance are the symptoms Q6. They are likely to promote better fluid intake than water.

Q1. Dehydration which is affected by genetics, body size, fitness, environment and exercise intensity.

Q2. Replace fluid as they are lost, drink plenty after exercise past point of quenching thirst, 200- 600mls before exercise commences

Q3. Because it does not become available to the body in that amount of time

Q4. Replace fluid every 15 minutes by drinking 150- 250mls of water during event

Q5. Fluid loss greater then 1% - 2% of total body weight, Thirst Irritability, Cramps, Headache, Nausea, Vomiting, Weakness, Head or neck heat sensations, Dizziness and Decreased performance are the symptoms

Q6. They are likely to promote better fluid intake than water.