Carbohydrate 2

Question 1

After exercise for CHO recovery what are the general guidelines for this ?

Answer 1

1-1.2g/kg/hour for 2-4 hours

Question 2

Because using glucose alone is limited at 60g hour uptake how can you increase this?

Answer 2

Ingest fructose as well as it used a different mechanism to move across the intestinal membrane.

uses GLUT5 instead of GLUT2

Uaing GLU + FRU can reach 100g/H

Question 3

Summary points from during exercise CHO feeding?

Answer 3

• CHO during prolonged exercise improves performance
• CHO ingestion spares endogenous stores
• Single maximum source intakes are 1g/min
• Multiple source intake of CHO and Fructose etc. can increase absorption rates
• Overall it is still limited by intestinal absorption.

Question 4

What is the exogenous carbohydrate oxidation (Intake carbs) limitation per mind during exercise ?

Answer 4

1g min

60g hour.

Question 5

If you have a 500ml drink that is 6% carbohydrate how many grams would that be ?

Answer 5

30g Carbs

6% equals 6g per 100ml

Question 6

How is exogenous CHO oxidation measured during exercise ?

Answer 6

A labeled CHO, C13 is ingested.

Amount of body stores in know

CO2 is measured as we have taken in a known amount. So we collect the CO2 and determine how much of this is from the isotope labeled CHO intake.

Question 7

What are the aims of nutritional recovery from exercise ?

Answer 7

• Ensure muscle and liver glycogen in restored.

Question 8

If the diet is low in carb what can me a method to ensure that better rates or glycogen synthesis can occur and how does this work ?

Answer 8

By adding protein there is a greater insulin response, allowing better CHO resynthesize. (0.3g/kg/h)

This is because the leucine in the protein drives the insulin response to a higher rate than carb alone.

This effect only assist with resythisis is carb is low, IF CHO is optimal protein adds no effect.

Question 9

Why have hydrogels become popular ?

Answer 9

Include pectin and sodium alginate which when they reach the acidic conditions of stomach encapsulate the carbohydrate. This increases gastric emptying.

Question 10

If an athlete is consuming a 15% carbohydrate drink during a three hour race what volume of this should they consume if running at a high intensity ?

Answer 10

15% equal 15g per 100m ml
High intensity exercise for three hours requires 90g/h
Lower intensities could may need 60g/h
90x3 = 270g
270/15 = 18
1800ml

OR
90g / 15 = 6
6x 100ml = 600
600x3 = 1800ml

Question 11

What is the limiting factor for exogenous carbohydrate oxidation?

Answer 11

|The amount that is transferred from the intestine into the blood.

IF it is infused straight into the blood the muscle can take it up.

Question 12

what are the current guidelines as suggested by Jeukendrup 2011 for CHO intake during events ?

Answer 12

>30min - None required
30-75min - very small amounts
1-2Hours - small amounts (ip to 30g/h
2-3Hours - Moderate amounts - Up to 60g/h
>2.5 hours - Large amounts - Up to 90g/h

Question 13

Is mouth rinsing a good source for performance?

Answer 13

Yes, in time trails al least