Carbohydrates And Exercise

Question 1

How many grams of carbs are stored in muscle, the liver, and blood

Answer 1

Muscle: 300-400 g

Liver: 75-100 g

Blood: 5-25 g

Question 2

How many mmol/kg does carbohydrate loading increase muscle glycogen stores?

Answer 2

210-230 mmol/kg

Question 3

What percentage of fuel does muscle glycogen and blood glucose account for in both moderate and high intensity exercise?

Answer 3

Moderate (65% of VO2 max): 50%

High intensity (85% of VO2 max): 66%

Question 4

What are daily carbohydrate intake guidelines for trained athletes

Answer 4

Very light training (low intensity or skill based): 3-5 g/kg

Moderate intensity (60 min/d): 5-7 g/kg

Moderate to high intensity endurance exercise (1-3 hr/d): 6-10 g/kg

Moderate to high intensity exercise (4-5 hr/d): 8-12 g/kg

Question 5

Formula for glycemic load

Answer 5

GL = GI (expressed as a decimal) x carbohydrate content (grams)

Question 6

What can a high GI modified starch do if consumed post exercise?

Answer 6

Enhance muscle glycogen storage

Question 7

What can a low GI modified starch do if consumed pre exercise?

Answer 7

Sustain blood glucose levels during prolonged endurance exercise

Question 8

What can carbohydrate loading do for performance

Answer 8

Postpone fatigue

Extend duration of steady state exercise by about 20%

Improve endurance performance by about 2-3%

Question 9

Modern way of doing glycogen supercompensation

Answer 9

Taper training for 3 days AND consume a high carbohydrate diet of 10 g/kg/d

OR

Rest for 36-48 hours AND consume 10-12 g/kg/d (new loading guideline)

Question 10

When is carbohydrate loading not going to work?

Answer 10

When exercise is less than 90 minutes

It may harm performance by causing stiffness and weight gain

Question 11

Benefits of consuming carbs

Answer 11

Restore liver glycogen

Increase muscle glycogen

Prevents hunger

Provides glucose for central nervous system

Question 12

Morning carbohydrate fueling recommendations

Answer 12

1-4 g/kg to be consumed 1-4 hours prior to exercise

Question 13

What nutrients should be limited before exercise?

Answer 13

Protein, fat, and fiber

Question 14

Rank from most to least effective:

Carbs consumed prior to exercise

Carbs consumed during exercise

Both

Answer 14

Both

Carbs consumed during exercise

Carbs consumed before exercise

Question 15

What are liquid meals good for?

Answer 15

Reducing nausea

Making weight due to low stool residue

Convenience for multiple or very long competitions

Question 16

Preventive strategies for experiencing hypoglycemia and fatigue following a carbohydrate feeding

Answer 16

Choose low GI sources (more stable glucose and insulin response)

Consume carbs a few minutes before exercise

Consume carbs during exercise

Question 17

What hormones inhibit the release of insulin?

Answer 17

Epinephrine

Norepinephrine

Growth hormone

Question 18

Consuming carbohydrates during exercise negates the glycemic effects of the pre exercise meal on performance and metabolism. T/F

Answer 18

True

Question 19

What are the benefits of consuming carbs during exercise?

Answer 19

Primarily metabolic:

Prevents hypoglycemia

Maintains high rates of carb oxidation

Improves endurance

Question 20

During prolonged exercise, what becomes an increasingly important fuel source?

Answer 20

Blood glucose

Because muscle glycogen stores decreased. By consuming carbs during exercise, carb oxidation (and therefore ATP production) remains high

Question 21

How do carbohydrate feedings improve performance in intermittent, high intensity sports?

Answer 21

Decrease muscle glycogen utilization

Increase muscle glycogen resynthesis during rest or low intensity periods

Increase blood glucose

Question 22

Maximum amount of glucose absorption during exercise

Answer 22

1 g/min

Question 23

How to exceed maximum carbohydrate absorption rate?

Answer 23

Pair glucose with FRUCTOSE

Question 24

At what hour of exercise does multiple transportable carbohydrates provide benefits?

Answer 24

2.5 hours or longer

Same benefit is provided as other carbohydrate sources lasting under 2.5 hours

Question 25

Recommended carbohydrate intake:

• Exercise lasting less than 30 minutes
• High intensity exercise lasting 30-75 minutes
• Endurance and intermittent, high intensity exercise lasting 1-2 hours
• Endurance exercise lasting 2-3 hours
• Endurance and ultra endurance exercise lasting 2.5 hours or more

Answer 25

30 or less: Not necessary or practical

30-75 minutes: Small amounts or a mouth rinse

1-2 hours: 30 g/hr and single or multiple

2-3 hours: 60 g/hr and single or multiple

2.5 or more: 90 g/hr and multiple transportable carbs

Question 26

Post exercise carbohydrate refueling recommendations

Answer 26

1.0-1.2 g/kg per hour for the first 4 hours

Question 27

There is no difference in glycogen resynthesis when liquid or solid forms of carbs are consumed.

T/F

Answer 27

True

Question 28

Why does glycogen depletion occur faster after exercise?

Answer 28

Blood flow to the muscles is greater immediately following exercise

Muscle cells are more likely to take up glucose

Muscle cells are more sensitive to the effects of insulin, which enhances the action of glycogen synthase

Question 29

Post exercise refueling recommendations for both carbs and protein

Answer 29

Carbs: 0.8 g/kg/hr

Protein: 0.3 g/kg/hr

Question 30

Consumption of 1-4 g/kg of carbs 1-4 hours prior to exercise results in __% improvement to ___________ performance

Answer 30

Improved endurance performance by as much as 14%

Question 31

List 3 examples of non-commercial intraworkout beverages

Answer 31

Fruit juice diluted in water (4 oz juice in 4 oz water = 6% solution)

Low sodium vegetable juices, such as carrot juice (7% solution)

Honey or solid foods ingested with water (8 oz for every 15 g of carbs = 6.3% solution)

Question 32

Why is maltodextrin no longer used

Answer 32

Causes GI upset