Hydration

Question 1

What percentage of body weight is made up of water?

Answer 1

About 55-60%.

Question 2

How is body water distributed?

Answer 2

Intracellular water: 2/3 of total body water (inside cells).
Extracellular water: 1/3 of total body water (outside cells, e.g., saliva, blood plasma).

Question 3

What factors influence body water storage?

Answer 3

Protein vs fat content: Muscle tissue holds more water than fat.
Carbohydrate content: 1g of glycogen stores 3g of water.
Electrolyte levels: Affect fluid movement in and out of cells

Question 4

Why does a low-carb diet lead to quick weight loss?

Answer 4

Glycogen stores are depleted, leading to water loss.

Question 5

How is body water regulated?

Answer 5

Physiological control: Hypothalamus, neurohypophysis, and kidneys.
Behavioural response: Drinking water to restore balance.

Question 6

What role does the neurohypophysis play in fluid balance?

Answer 6

It releases vasopressin (helps retain water) and oxytocin.

Question 7

What is the normal body water turnover for sedentary adults?

Answer 7

1-3L per day

Question 8

Where does water loss occur during exercise?

Answer 8

Skin (sweating)
Urinary system
GI tract
Respiratory system (breathing out moisture)

Question 9

How is water gained?

Answer 9

Food and drink intake
Intravenous fluids (if medically needed)

Question 10

How do kidneys regulate fluid balance?

Answer 10

They adjust urine production based on body water levels.

Question 11

What are the main roles of water in the body?

Answer 11

Transports oxygen and nutrients
Removes CO2 and waste
Regulates pH
Dissipates heat during exercise
Maintains blood pressure
Supports cardiovascular function and performance

Question 12

What happens if hydration is not maintained?

Answer 12

Decreased performance, increased core temperature, cardiovascular strain.

Question 13

How can hydration needs be estimated?

Answer 13

By tracking body weight changes before and after exercise.

Question 14

How much fluid should be consumed post-exercise for rapid rehydration?

Answer 14

24 oz (≈700 ml) per 1 lb (≈0.45 kg) body weight lost.

Question 15

What is euhydration?

Answer 15

A normal state of body water.

Question 16

What is hyperhydration?

Answer 16

Physiological state of too much total body water

Question 17

What is hypohydration?

Answer 17

Physiological state of too little total body water

Question 18

What is dehydration?

Answer 18

The process of losing body water.

Question 19

What is rehydration?

Answer 19

The process of gaining body water.

Question 20

How does the body lose water at rest?

Answer 20

Through insensible water loss (skin, breathing, stool) and measurable losses (urine, sweat)

Question 21

What factors influence water loss during exercise?

Answer 21

Temperature and humidity
Air velocity
Body size and metabolic rate
Genetics

Question 22

What risks do water sport athletes face?

Answer 22

Sweat loss still occurs but is harder to detect, increasing dehydration risk.

Question 23

What are electrolytes?

Answer 23

Minerals with an electric charge, essential for fluid balance.

Question 24

Which electrolyte is lost most in sweat?

Answer 24

Sodium (greatest quantity).
Potassium (lost in smaller amounts).

Question 25

Where are sodium and potassium found in the body?

Answer 25

Sodium: Extracellular space. Potassium: Intracellular space.

Question 26

What can sodium deficiency cause?

Answer 26

Muscle cramps and fluid imbalance.

Question 27

What is hyponatremia?

Answer 27

Low sodium concentration in the blood.

Question 28

What is hypernatremia?

Answer 28

High sodium concentration in the blood.

Question 29

How does hypohydration impact the body?

Answer 29

Reduces ability to remove heat. Increases cardiovascular strain. Increases glycogen use. Alters metabolic and central nervous system (CNS) function.

Question 30

How does dehydration affect performance?

Answer 30

>2% loss = impaired cognitive & aerobic performance. 3-5% loss = decreased anaerobic performance, sport skills.

Question 31

What are the classifications of dehydration?

Answer 31

Mild: 2% body mass loss. Moderate: 5% loss. Severe: 10% loss (can lead to heat stroke/death).

Question 32

What are pre-exercise hydration recommendations?

Answer 32

Start hydrated (3-4 hours before). Consume 5-7 ml/kg body mass with sodium.

Question 33

What are during-exercise hydration recommendations?

Answer 33

Drink to thirst. Use carbohydrate-electrolyte solutions.

Question 34

What are post-exercise hydration recommendations?

Answer 34

Replace 150% of body mass lost. Include sodium (50-110 mmol) to slow urination. Use PHIZZ and HYDRA 10 products if available.

Question 35

How much fluid should be consumed pre-exercise?

Answer 35

5-10 ml/kg body weight 2-4 hours before exercise.

Question 36

How should fluids be consumed during exercise?

Answer 36

Regularly and early before feeling thirsty. Intake should match sweat loss.

Question 37

Why should sodium be included in hydration strategies?

Answer 37

It helps retain water and prevent dehydration.

Question 38

What are the effects of carbohydrate concentration in drinks?

Answer 38

Too high (>10% CHO): Slows gastric emptying, causing GI distress. Optimal (4-8% CHO): Balances hydration and energy intake.

Question 39

How much sodium should be in a sports drink?

Answer 39

0.5-0.7 g/L water.

Question 40

What is diuresis and how can it be avoided?

Answer 40

Increased level of urine The slowing of rehydration fluid can be achieved by a drinking pattern or by delaying gastric emptying of the drink from the stomach into the intestine by increasing the carbohydrate content of the drink

Question 41

What is hypotonic?

Answer 41

A lower concentration of fluid, sugars and salt than blood

Question 42

What is hypertonic?

Answer 42

A higher concentration of fluid, sugars and salt than blood

Question 43

What is isotonic?

Answer 43

A similar concentration of fluid, sugars and salt to blood

Question 44

How do electrolytes assist thermoregulation?

Answer 44

Water follows electrolytes When it gets too warm during exercise electrolytes move to our sweat glands allowing water to follow Then the water on the skin is evaporated to help you cool down

Question 45

What does urine colour indicate?

Answer 45

Pale yellow = hydrated. Dark yellow = dehydration.

Question 46

What is the best way to replace lost fluids?

Answer 46

Consume 125-150% of fluid lost with electrolytes

Question 47

What are the main methods used to monitor hydration status?

Answer 47

Urine analysis (color, osmolality, specific gravity, volume). Body mass changes (before and after exercise). Plasma osmolality (blood test). Bioelectrical impedance analysis (BIA). Salivary and tear sample analysis. Thirst perception.

Question 48

How does urine specific gravity (USG) help assess hydration?

Answer 48

Measures urine concentration by comparing its density to distilled water. A higher USG indicates dehydration. A lower USG suggests proper hydration.

Question 49

What is urine osmolality, and how is it used?

Answer 49

Measures urine concentration based on solute particles. Higher values = dehydration (more concentrated urine). Lower values = good hydration (more diluted urine).

Question 50

What are the limitations of using urine osmolality for hydration assessment?

Answer 50

Can be influenced by diet (electrolytes, protein, carbs), medications (caffeine, alcohol), and illnesses (kidney disease, diabetes). Does not provide real-time hydration status, only renal response.

Question 51

Why might urine colour not be the most reliable method?

Answer 51

Subjective assessment (depends on lighting, perception). Affected by diet and supplements (e.g., vitamins can darken urine).

Question 52

How does measuring body mass changes help track hydration?

Answer 52

1 kg of weight loss = approximately 1 L of fluid lost. Useful for monitoring acute dehydration and rehydration strategies. Best measured before and after exercise.

Question 53

What are the advantages and limitations of body mass monitoring?

Answer 53

Advantages: Simple, fast, and non-invasive. Reliable when fluid loss is primary reason for weight change. Limitations: Can be affected by food intake, muscle glycogen levels, or other body changes.

Question 54

How does plasma osmolality assess hydration status?

Answer 54

Measures concentration of solutes in blood plasma. Higher plasma osmolality indicates dehydration. Considered one of the most accurate hydration assessments.

Question 55

What are the limitations of plasma osmolality tests?

Answer 55

Invasive: Requires blood sampling. Expensive and time-consuming. Affected by exercise, diet, and overall health.

Question 56

What is bioelectrical impedance analysis (BIA), and how does it assess hydration?

Answer 56

Measures total body water by sending a low electrical current through the body. More water = faster electrical signal. Less water (dehydration) = slower signal due to increased resistance.

Question 57

What factors can affect bioelectrical impedance accuracy?

Answer 57

Posture and movement. Skin temperature and electrolyte balance. Recent food or fluid intake. Exercise and alcohol consumption.

Question 58

Why is thirst perception not always a reliable hydration indicator?

Answer 58

Thirst lags behind actual dehydration. Some individuals (e.g., elderly, athletes) may not feel thirsty despite fluid loss. By the time thirst is felt, dehydration may already be significant.

Question 59

What are some less common hydration monitoring methods?

Answer 59

Salivary flow rate and composition: Can indicate dehydration but is affected by diet and stress. Tear osmolality: Measures tear concentration, but not widely used.

Question 60

Which hydration monitoring method is best for athletes?

Answer 60

Combination of methods is ideal (e.g., body mass changes + urine analysis + thirst perception). Plasma osmolality is best but impractical for daily use. Urine colour and body mass tracking are the most practical for regular use.