Carbohydrate Feeding- During Exercise W3 Flashcards
What do fast and slow carbohydrates refer too?
The speed at which these carbohydrates types are digested, absorbed and made available to the body for energy provision
What are fast carbohydrates
Glucose
Maltose
Sucrose
Maltodextrins
Starches rich in amylopectin
What are slow carbohydrates?
Fructose alone
Galactose
Isomaltulose
Starches rich in amylose
What is the classic guideline amount for carbohydrate feeding during exercise?
1.0 g/min (60g/h) during exercise
What is the recommended type of carbohydrates for exercise that last >2.5 hours?
Only multiple transportable carbohydrates
90 g/hour
What is the recommended type of carbohydrates for exercise that lasts between 30-75 minutes?
Single or multiple transportable carbohydrates
Small amounts or mouth rinse
What is the recommended type of carbohydrates for exercise that lasts between 1-2 hours?
Single or multiple transportable carbohydrates
30 g/hour
What is the recommended type of carbohydrates for exercise that lasts between 2-3 hours?
Single or multiple carbohydrates
60 g/hour
What are the metabolic effects of carbohydrate feeding during exercise?
Spares muscle glycogen (not often observed)
Sustains liver glycogen (sustains plasma glucose)
Sustains high rates of carbohydrate oxidation and maintains plasma glucose concentration
What is faster, glucose or glucose fructose?
Glucose fructose
How much carbohydrate (g/h) should you have in an exercise bout lasting more than 180 minutes?
90g/h
How much carbohydrate (g/h) should you have in an exercise bout lasting 60-180 minutes?
30-60g/h
What are multiple transportable carbohydrates?
Refers to sugars that are transported across the intestine by stimulating more than 1 protein tranpsorter
What is glucose protein transporter? (also galactose)
SGLT1
What is fructose protein transporter?
GLUT5
What do multiple transportable carbohydrates do?
Increases exogenous carbohydrate oxidation by 20-50%
Improves gut comfort
Enhances performance in prolonged, intense exercise
What are the disaccharides? (3)
Lactose
Maltose
Sucrose
What are the monosaccharides? (3)
Galactose
Glucose
Fructose
What are the 2 starches?
Amylose
Amylopectin
What does exogenous mean?
Outside the body
What is an example of a multiple transportable carbohydrate?
Glucose-fructose
What happens to exogenous CHO oxidation relationship during low-moderate CHO ingestion rate?
Linear relationship
What is the ceiling effect of exogenous oxidation rate?
1.2g/min
When do you get performance benefits from CHO ingestion?
About 45 minutes
What is endurance capacity?
Time to fatigue (fixed rate)
Measured in time/distance
What is endurance performance?
Defined finishing line
Race scenario
What is the primary reason for performance benefit?
Maintaining high rates CHO oxidation during exercise
What type of muscle fibre has “sparing”?
Type I
What are the non-metabolic benefits from carbohydrate ingestion?
Reduces motor recruitment
Reduces power output
(from negative signals)
Why may oxidation rate in the stomach be impaired?
Intestinal transport limitation
- Only so many membranes working at a maximal rate
How can you prevent intestinal transport limitations?
Co-ingestion with carbohydrates with 2 different sugars and 2 transport mechanisms
What is the main limitation to exogenous oxidation?
Intestinal carbohydrate oxidation
What are the recommendations of carbohydrate intake scaled too?
Duration (some extent intensity)
