Chapter 11: Hydration

Question 1

Intracellular Fluid (ICF)

Answer 1

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

Question 2

Extracellular Fluid (ECF)

Answer 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.

Question 3

Osmolality

Answer 3

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.

Question 4

Dipsogenic Signal

Answer 4

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

Question 5

Baroreceptors

Answer 5

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

Question 6

Hypo-Osmotic

Answer 6

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

Question 7

Gastric Emptying Rate (GER)

Answer 7

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 GER, 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 8

Convection

Answer 8

The movement or flow of air over an object.

Question 9

Euhydration

Answer 9

A normal hydration status.

Question 10

Ad Libitum

Answer 10

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

Question 11

Exercise Associated - Hyponatremia (EAH)

Answer 11

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.

Question 12

Urine-Specific Gravity (USG)

Answer 12

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

Question 13

Recovery Hydration

Answer 13

Fluid and electrolyte intake between two consecutive training sessions or competitions.

Question 14

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

Answer 14

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

Question 15

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

Answer 15

ECF Osmolality

Question 16

What other factors, aside from hydration status, can contribute to heat illness? Check all that apply.

Answer 16

Heat, Humidity, Convection

Question 17

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

Answer 17

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

Question 18

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 18

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

Question 19

Because the use of osmolality and specific gravity strategies when determining hydration strategies are often impractical, a urine chart is often used to educate clients on their hydration status. Why is it important to collect and analyze urine in a clear container versus the toilet?

Answer 19

The urine in the toilet is diluted from the toilet water and will portray a false color indication used to compare with the Urine Color Chart.

Question 20

Which of the following symptoms may be indicative of exertional rhabdomyolysis?

Answer 20

Extremely-dark-colored urine

Question 21

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

Answer 21

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

Question 22

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

Answer 22

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 23

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 23

“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 24

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 24

Begin the race euhydrated and simply drink to thirst.

Question 25

A client’s pre-exercise weight is 75.0 kg. Their post-exercise weight is 73.5 kg. They consumed 0.25 liters of fluid during training. What was the volume of their sweat loss?

Answer 25

1.75 liters

Question 26

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

Answer 26

They significantly underestimate their sweat losses.

Question 27

Which of the following scenarios would create the most optimal conditions for decreasing body temperature increase during exercise if the temperature and humidity were equal under each training scenario?

Answer 27

Cycling for an hour outdoors at 20 miles/hour

Question 28

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 28

3.0 liters

Question 29

When assessing a client’s sweat losses, a Nutrition Coach determines that their change in body mass is approximately 1.5 kg. How many liters of sweat does this equal?

Answer 29

1.5 liters

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

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

Answer 31

Baroreceptor

Question 32

A client has repeatedly exhibited a pre-exercise USG range between 1.028 and 1.032. How would a Nutrition Coach interpret this finding?

Answer 32

The client needs to increase their fluid intake between training bouts.

Question 33

A client weighs 70 kg and is training to complete a marathon in a time of about 4 h. The client’s sweat losses are expected to equal around 4 liters (about 6% of body mass). Which fluid intake goal would be most appropriate?

Answer 33

Drink 2 liters of fluid during the race.

Question 34

Urine-specific gravity is best assessed with which tool?

Answer 34

Refractometer