Carbohydrate Supplementation Flashcards

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1
Q

What are the three general locations glycogen/glucose can be stored?

A
  • liver
  • muscle
  • blood
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2
Q

Which glycogen store provides the largest amount for exercise duration?

  1. liver
  2. muscle
  3. blood
A
  1. muscle
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3
Q

In grams in the average person how much glycogen is found in the liver?

A

80-100g

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4
Q

In grams in the average person how much glycogen is found in the blood?

A

20g- 4-5mmol/l

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5
Q

In grams in the average person how much glycogen is found in the muscle?

A

300-800g

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6
Q

In which parts of the GI tract does CHO digestion take place?

A

Buccal cavity/mouth

Small intestine

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7
Q

True or False: There is a small amount of CHO digestion in the stomach

A

False- no CHO digestion occurs here

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8
Q

Give 3 types of CHO, and the enzymes needed to break them down

A

Starch –> Amylase
Maltose –> Maltase
Lactose –> Lactase
Sucrose –> Sucrase

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9
Q

Which CHO forms glucose and fructose when digested

A

Sucrose

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10
Q

Which CHO forms glucose when digested

A

Maltose

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11
Q

How is glucose absorbed into the intestine

A

Co-transported with Na

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12
Q

How is fructose absorbed into the intestine

A

Co-transported with GLut-5

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13
Q

Which Glut transporter do glucose/fructose use to enter the blood

A

Glut 2

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14
Q

What is the maximal rate of CHO absorption

A

60g/h

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15
Q

Give an overview of the glycolysis process

A

Glucose –> G-1-P –> G-6-P –> F 1,6-BP –> Glyceraldehyde-3-P ——-> Pyruvate

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16
Q

What are the products of glycolysis

A

Pyruvate
NADH
ATP

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17
Q

How is pyruvate converted into acetyl co-A

A

Pyruvate + CoA + NADH -CO2 = Acetyl CoA

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18
Q

What are the products of the krebs cycle

A
CoA
CO2
NADH
GTP
FADH2
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19
Q

What is the final electron acceptor in the ETC

A

Oxygen

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20
Q

What are the products of the ETC

A
NAD
FAD
H20
ATP
H+
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21
Q

How does increased CHO affect time to exhaustion

A

Greater time to exhaustion

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22
Q

Which fuel is predominant >60% VO2 max

A

Fat

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23
Q

Which fuel is predominant <60% VO2 max

A

CHO

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24
Q

Describe the classic supercompensation CHO loading protocol

A

Intense training 7 days prior to event to deplete CHO stores with low CHO diet. Then 3 days before the race, have a high CHO diet (supercompensation)

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25
Q

Give 2 disadvantages of the classic supercompensation CHO loading protocol

A

could lead to hypoglycaemia in the low CHO phase, GI distress, poor recovery and a negative mental state

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26
Q

Describe the moderate supercompensation CHO loading protocol

A

Gradually increase the CHO quantity consumed in the 7 days prior to the race, as well as decreasing the intensity of training

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27
Q

How do CHO levels differ between the classic and moderate supercompensation protocols- study results not protocol type

A

the classic protocol boosts higher CHO levels, 60 minutes into performance,
Otherwise there is no observed difference in CHO levels between the 2 protocols.

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28
Q

True or False: studies suggest 1 day of high CHO consumption prior to exercise may be enough for these performance benefits

A

True- As long as there wasn’t exercise performed the day before.

29
Q

Everyday, what is a sufficient CHO intake level (g/kg/d)

A

5-7 g/kg/day

30
Q

What is one negative of CHO generally

A

• GI problems- so athletes need to be careful about how much/the form

31
Q

3-5 hours prior to performance, what are the benefits of a large CHO rich meal

A
  • Should maximise glycogen in liver and muscle
  • Can improve performance
  • Decreased fat and fibre- effects length of time in intestine
32
Q

At exercise onset, what happens to plasma glucose levels

A

Transient fall

33
Q

When increased CHO oxidation occurs, giving an accelerated glycogen breakdown- how does this effect fat

A

blunting of FA mobilisation and fat oxidation

34
Q

What is the issue with taking in a large amount of CHO 30-60 mins prior to exercise

A

Causes a large rise in plasma glucose and insulin

Can lead to reactive/rebound hypoglycaemia during exercise

35
Q

Define the Glycaemic Index

A

Response to 50g CHO compared to 50g glucose

36
Q

Give 2 factors which influence the glycaemic index

A

o Food particle size
o Biochemical structure
o Co-ingestion of fat/fibre/protein
o Gastric emptying, digestion and absorption

37
Q

A lower GI gives a ——- insulin response?

A

lower

38
Q

Does glucose or fructose have a lower GI. How is this beneficial?

A

Fructose lower. Reduces likelihood of crashing.

39
Q

Can CHO be beneficial for intermittent exercise as well as endurance?

A

Yes by feeding CHO during exercise, muscle glycogen levels reduced less than the placebo.

40
Q

Can CHO be beneficial for technical skills i.e. tennis serve?

A

CHO supplementation increased stroke quality in tennis, and was beneficial for high pressure situations, or those which require explosiveness.

41
Q

GIve 3 examples of rapidly oxidised CHOs

A
Glucose
Sucrose
Maltose
Lactose
Maltodextrins
Soluble Starch (amylopectin)
42
Q

GIve 3 examples of less rapidly oxidised CHOs

A

Fructose (liver)
Galactose (liver)
Insoluble starch (amylose)

43
Q

At what g/min does rapidly oxidised mean

A

up to 1g/min

44
Q

At what g/min does less rapidly oxidised mean

A

up to 0.5g/min

45
Q

To what g/min rate is oxidation limited too

A

1g/min

46
Q

Why can glucose levels become fully saturated

A

Only utilises 1 transporter

47
Q

How can we improve CHO oxidation rates

A

Ingesting both glucose and fructose increases oxidation rates (1.26g/min), as they use different transporters.

48
Q

True or False: the form of CHO ingested affects the performance of CHO oxidation

A

False

49
Q

What can be used for those who suffer GI distress from glucose

A

CHO mouth rinse

50
Q

What % glucose is often found in a mouth rinse?

A

12.5%

51
Q

Why is performance enhanced with multiple sources of CHO

A

They use different transporters, so more CHO generally can be absorbed in a time

52
Q

At <30min duration how much CHO is needed

A

None

53
Q

At 30-75 min duration, how much CHO is needed

A

Small amounts i.e. mouthrinse

54
Q

AT 1-2h duration, how much CHO is needed

A

30g/h most types

55
Q

At 2-3h duration, how much CHO is needed

A

60g/h rapidly oxidised forms

56
Q

At >3h duration, how much CHO is needed

A

Up to 90g/h multiple CHO transporters

57
Q

With CHO supplementation, how might a diet change fat, fibre and protein consumption

A

should be low in fat and fibre and contain protein if it can be tolerated

58
Q

True or False: CHO ingested during exercise will “spare” liver glycogen and can completely block hepatic glucose output

A

True

59
Q

True or False: Ingestion of multiple transportable CHO can increase exogenous carbohydrate oxidation rates by 40-60%

A

False- 20-50%

60
Q

Why should CHO be used during recovery?

A

to maintain/restore muscle glycogen concentrations for future performance.

61
Q

Give 3 factors that may affect glycogen resynthesis

A
  • Timing
  • Amount
  • Form
  • Type
  • Other nutrients
62
Q

What glut receptor response does exercise stimulate

A

Glut 4 translocation

63
Q

How does glycogen resynthesis affect the insulin response, and why

A

Increases insulin response, as it stimulates glycogen synthase

64
Q

What are the maximal glycogen resynthesis rates

A

1.2-1.4g/min ~70-90g/hour

65
Q

Why could liquid forms of CHO be preferential?

A

liquid forms are fluid, so contribute to rehydration. They are easier to consume when appetite is reduced, and easy to digest.

66
Q

Which two CHO’s are most favourable for recovery:

  1. Glucose, Sucrose
  2. Glucose, fructose,
  3. Fructose, sucrose
A
  1. Glucose, Sucrose
67
Q

Why is fructose less favourable for recovery

A

absorbed slower. It has a lower GI, and minimal insulin response (which is not favourable as we want to stimulate glut-4 translocation, which require the insulin response)

68
Q

Where can fructose be more favourable during recovery

A

The liver

69
Q

For recovery, do we want foods with a high or lower GI

A

Higher