Chapter 11: Hydration

Question 1

The water contained within a cell’s membrane, makes up approximately 2/3 of total body water.

Answer 1

Intracellular Fluid (ICF)

Question 2

The water found outside of the body’s cells – ECF is found between cells and transported throughout the body via arteries, veins, and capillaries.

Answer 2

Extracellular Fluid (ECF)

Question 3

What percentage of the total body mass is water?

Answer 3

50-70%

Question 4

Describes the concentration of solutes in a liquid – various compartments hold fluids but the primary regulator of hydration status is the osmolality of ECF, specifically plasma osmolality. Multiple sites in the body house osmoreceptors that detect shifts in osmolality and generate responses to return the body to fluid and sodium homeostasis.

Answer 4

Osmolality

Question 5

Physiological factors such as high osmolality or low blood pressure, which prompt sodium and water appetite.

Answer 5

Dipsogenic Signal

Question 6

Specialized nerves that can sense change in pressure in the heart or blood vessels.

Answer 6

Baroreceptors

Question 7

A solution with a lesser concentration of solute (i.e., fresh water compared to salt water).

Answer 7

Hypo-Osmotic

Question 8

A key driver of thirst. If you are working with athletes who need to replace large volumes of sweat lost, consuming meals or snacks with sodium will promote a natural increase in fluid intake and also aid in retention of ingested fluids.

Answer 8

Plasma osmolality

Question 9

Gastric Emptying Rate (GER)

Answer 9

The rate at which fluids and their contents pass through the stomach via the pyloric sphincter and into the small intestine – the faster and more complete the ___, the more quickly carbohydrates and electrolytes can be absorbed into the mesentery system, where they feed the liver first and then the rest of the body via the vascular system.

Question 10

What are the 3 primary Involuntary actions that change the levels of fluid and electrolytes in the body?

Answer 10

Food & Beverage Intake, Urine loss during recovery, Sweat loss during exercise

Question 11

What is the most significant influence-to-thirst for water?

Answer 11

ECF Osmolality

Question 12

The movement or flow of air over an object.

Answer 12

Convection

Question 13

A normal hydration status.

Answer 13

Euhydration

Question 14

Translates to “as desired” and refers to eating or drinking as you are normally driven to (i.e., not purposely overeating or undereating).

Answer 14

Ad Libitum

Question 15

What other factors, aside from hydration status, can contribute to heat illness?

Answer 15

Humidity, convection, heat, Clothing choice, Body composition, Training status, Level of exertion, Environmental conditions

Question 16

A potentially serious medical condition in which the plasma sodium falls below 135 mmol/L, usually the result of fluid intake greatly exceeding sweat losses during prolonged exercise.

Answer 16

Exercise Associated Hyponatremia (EAH)

Question 17

In most cases, calculating the average client’s sweat loss is not necessary. However, for those clients that require a level of coaching where it is required, which equation provided yields a client’s sweat loss volume kilograms?

Answer 17

Initial Weight (kg) – Post-exercise weight (kg) + fluid consumption during (kg) – Urine volume (kg)

Question 18

There has been much discussion about the risk of Exercise-Associated Hyponatremia (EAH). Without diagnosing, what are some less severe symptoms that a client could exhibit who might be experiencing EAH often confused with severe dehydration?

Answer 18

Weakness, cramping, disorientation, vomiting, confusion

Question 19

A measurement that represents the ratio of solutes in the urine versus distilled water.

Answer 19

Urine-Specific Gravity (USG)

Question 20

Where is approximately 2/3 of body water found?

Answer 20

Intracellular fluid

Question 21

What is the minimum percentage of beverage fluid replacement range that should be suggested for clients who lose more than 3% of their body mass during training and train more than once over a 24-hour period?

Answer 21

110-120%

Question 22

A client completes three weight-training sessions with a Personal Trainer per week but also completes three, 1-hour group indoor cycle per week (not on the same day). They ask their Nutrition Coach for hydration advice. Which of the following responses would be most appropriate?

Answer 22

“Your workout sessions are not long enough in duration to cause sweat losses that dictate a personal hydration plan. Keep fluids available during exercise, and drink based on thirst.”

Question 23

For clients engaged in prolonged endurance events who know what their sweat losses will be, which is the most appropriate advice to give in regards to developing a competition hydration strategy?

Answer 23

Do not drink in excess of sweat losses and limit body mass loss to < 3-4%.

Question 24

What role does pickle juice play in regards to client hydration status?

Answer 24

Pickle juice contains a high concentration of sodium which can increase thirst drive and aid in consumed fluid retention.

Question 25

Which individual would be most likely to be at risk for exercise associated hyponatremia?

Answer 25

A runner completing a 4.5 hour marathon in cool weather.

Question 26

Which of the following compounds can passively cross a cell membrane?

Answer 26

Water

Question 27

Which of the following electrolytes is found in the greatest concentration in the extracellular fluid?

Answer 27

Sodium

Question 28

A sweat-loss assessment has determined a client loses about 1.5 % of their body mass during a typical training session. The client trains 5 days per week. What is the best hydration advice for this client?

Answer 28

Drink ad libitum. If this does not assure the client, advise an extra 500 mL of water before bed and before reporting to train.

Question 29

Which of the following electrolytes is found in the greatest concentration in the intracellular fluid?

Answer 29

Potassium

Question 30

A client who trains for triathlons has asked how much fluid he should consume between his morning runs and afternoon bike rides. He has determined his sweat losses from his early morning runs average around 2 liters. Which range of fluid intake would be most appropriate?

Answer 30

2.5-3.0 liters

Question 31

A client’s pre-exercise weight is 80.0 kg. Their post-exercise weight is 78.0 kg. They consumed 1.0 liters of fluid during training. What was the volume of their sweat loss?

Answer 31

3.0 liters

Question 32

Which item most appropriately describes the use of urine-specific gravity?

Answer 32

It should be assessed multiple times before exercise to determine if clients with heavy sweat losses routinely fail to consume adequate fluid during recovery.

Question 33

What is the primary cause of exertional rhabdomyolysis?

Answer 33

An intense exercise session

Question 34

Which of the following has research shown is true regarding most individuals engaged in training that produces significant sweat losses?

Answer 34

They significantly underestimate their sweat losses.

Question 35

What signaling mechanism triggers thirst due to a significant loss in total body water from sweating?

Answer 35

Baroreceptor

Question 36

A client has repeatedly exhibited a pre-exercise USG range between 1.014 and 1.018. How would a Nutrition Coach interpret this finding?

Answer 36

The client is doing a great job of meeting recovery fluid intake needs.

Question 37

Which item most accurately describes the role of fluid intake in regards to assisting body-temperature regulation during exercise in the heat?

Answer 37

Fluid intake can blunt increases in temperature during severe dehydration, but it cannot prevent all cases of heat illness.

Question 38

A client weighs 50 kg and is training to complete a cool weather half-marathon in a time of about 2 h. The client’s sweat losses are expected to equal 2 liters (about 4% of body mass). Which fluid intake goal would be most appropriate?

Answer 38

Begin the race euhydrated and simply drink to thirst.