Carbohydrate (CHO) And Sport Flashcards
-ase
Enzyme
Breaks things down
-ose
Carb, sugar, glucose
How do we know what system athlete primarily uses
Must know how they compete and train
ATP-PCR system
Relies on breakdown of stored ATP and PCR to resynthesize ATP
Lactic acid system
Relies on anaerobic breakdown of glycogen to resynthesize ATP (anaerobic glycolysis)
Aerobic system
Relies on aerobic breakdown of glycogen to resynthesize ATP (aerobic glycolysis)
How are CHO classified
By structure
What is primary fuel for muscle contraction
CHO
Simple CHO
Sugars: monosaccharides and disaccharides
monosaccharides
Glucose
Fructose
Galactose
Disaccharides
Maltose
Lactose
Sucrose
Complex CHO
Starches (polysaccharides)
Glucose polymers (maltodextrins)
Fibers
Glycogen
Polysaccharides
Starches
Maltodextrin (glucose polymers)
Fibers
Glycogen
Maltodextrin
Complex carb used in sport nutrition products
Nutrient dense carb
Foods and fluids that are rich sources of other nutrients including protein, vitamins, minerals, fibre and antioxidants in addition to CHO
Examples of nutrient dense foods
Breads and cereals, grains, fruit, starchy vegetables, legumes and low fat dairy products
How are nutrient dense carbs used for athletes
Everyday food that should form base of an athletes diet
Helps to meet other nutrient targets
Nutrient poor carbs
Foods and fluids that contain CHO but minimal or no other nutrients
Examples of nutrient poor carbs
Soft drink, energy drinks, gels, candies and sports drinks
Nutrient poor carb use for athletes
Shouldn’t be major part of everyday diet but may provide a compact carb source around training
Acute fueling strategy
Higher fat/slower digestion carb
Foods that contain CHO but are high in fat
Examples of higher fat/slower digestion
Pastries, cakes, chips and chocolate
Higher fat/slow digestion carb use for athletes
Sometimes foods best not consumed around training sessions
Bunch of fat before will take long time to digest
Simple CHOs
Glucose
Fructose
Galactose
Sucrose
Complex CHOs
Amylose
Amylopectin
Rapid absorption
Glucose
Maltose
Sucrose
Maltodextrins
Amylopectin
Slower absorption
Fructose
Galactose
Trehalose
Isomaltulose
Amylose
What increases transport
Combining different carbs
Ex) Maltodextrin- glucose + fructose
Following a meal containing CHO what will rise
Blood glucose
Maintenance of stable blood glucose is critical
what does the rise of blood glucose stimulate
Pancreas to release insulin into the blood
What does insulin do
Facilitates uptake of glucose by various tissues within the body (muscle and fat cells)
What do the various tissues that can uptake glucose contain
Receptors which are activated by insulin
Transporters get glucose into bloodstream
What else activates the receptors
Exercise activates receptors to transport glucose from blood into muscle tissue independent of insulin
What will glucose be used by
Brain, CNS, and RBCs
Dependent on glucose for their fuel needs/metabolism
What is glucose stored as when fuel is not needed by body
Muscle and/or liver glycogen
If large amounts of simple sugars consumed what happens
Blood glucose may be excreted in urine
How will excess glucose be converted and stored
As body fat
In adipose tissue
When does conversion of glucose to body fat occur
When dietary CHO (in combination with caloric intake of other macronutrients) exceeds the energy demands of the body and exceeds the storage capacity within the muscle and liver (glycogen)
What is critical for exercise performance
Maintaining liver/muscle glycogen and blood glucose
What causes glucose uptake
Insulin and exercise increases glucose uptake
How much energy does CHO supply at rest
40% with 15-20% used by muscle
During exercise what happens with CHO oxidation
Increases in proportion to exercise intensity
As we need more ATP, as length increase
When does CHO become dominant fuel source
> 65-70% VO2 max
- depending on training status of individual
As exercise intensity increases
Lactate and H+ accumulates and may increase fatigue
What is important for prolonged endurance exercise (>1-2hr aerobic training)
CHO intake
What is essential for moderate to high intensity intermittent sports (hockey, football, soccer)
CHO
Why is CHO so vital for exercise
- Body contains relatively limited endogenous stores (diet dependent)
- Can be acutely manipulated on daily basis by usage (aerobic training) and storage
- Key fuel source for brain and CNS
- More efficient
- Can be used in anaerobic and aerobic/oxidative energy production pathways
What is the only source for anaerobic energy production in lactic acid system
CHO
What needs more oxygen to be metabolized than CHO
Fat
How are the metabolic pathways more efficient for CHO than fat
CHO produces ATP up to 3x faster than fat in aerobic glycolysis
Internal CHO sources of energy during exercise are
Blood glucose 5g; 20 cals
Liver glycogen 75-100g; 300-400cals
Muscle glycogen 300-400g; 1200-1600cals
As muscle glycogen is being used what happens
Blood glucose enters muscle cell
When blood glucose enters muscle cell what happens
Liver releases glucose to maintain blood glucose levels (homeostasis)
- helps prevent hypoglycemia
During moderate intensity exercise what contribute to CHO oxidation
Liver and muscle contribute equally
As exercise intensity increases what contributes to CHO oxidation
Muscle glycogen provides the majority of glucose
How can you improve performance in high intensity aerobic exercise
Match CHO intake to fuel needs
When decrease CHO stores and no replacement with exogenous CHO
Increased fatigue
Decreased work rate
Impaired skill
Impaired concentration
Increasing rating of perceived exertion (RPE)
Summary of athletes plate on hard training day/race day
Half grains
1/4 lean protein
1/4 vegetables
Fresh fruit
Drink
2 tbsps fats
