Carbohydrates Flashcards
True or False
Aerobic glycolysis provides ATP at a faster rate than oxidation fats
True
True or False
During prolonged exercise sessions (>90min) CHO becomes a limiting factor
True
How much glycogen is in muscle?
200-500g
How much glycogen is in liver?
60-120g
What are the 2 types of Glycogen particles?
- Proglycogen (15%) - First particles to add glucose units after depletion
- Macroglycogen (85%) - slower to add glucose units
What are the 3 roles of glycogen relevant to exercise performance?
- Fuel sensor
- Regulates signalling pathways involved in training adaptation
- Glucose homeostasis: 80g stored liver glycogen constantly replenish 4g blood glucose. At rest 60% of glucose in blood goes to the brain.
How much CHO for light training?
3-5 g/kg/day
How much CHO for moderate (1 hr/day) training?
5-7 g/kg/day
How much CHO for high (endurance 1-3 hr/day) training?
6-10 g/kg/day
How much CHO for very high (endurance 4-5 hr/day) training?
8-12 g/kg/day
How many gr of water are stored for every gr of CHO?
3g
Who should carb load?
- marathon and triathlons
- events lasting >90 min
Which menstrual phase affects CHO loading in women?
Follicular and luteal phase. Women need ~ 10 g.kg-d to
super-compensate
What are the determinants of effectiveness of CHO loading in women?
- Total energy intake
- Total carbohydrate intake
- Phase of menstrual cycle
CHO Recommendation for women:
Eat CHO rich diet the day before competition and consume high CHO meal/snack 3-4 hrs before competition
CHO Practical Guidelines
*Start exercise with sufficient muscle glycogen
* Trained individuals should eat carbohydrate
rich for 2 days prior to a race, whilst reducing glycogen use (reducing training)
* Don’t overeat - higher carbohydrate intake
should not be the result of just eating more
* Choose either solid and liquid carbohydrate
sources, high GI seems to be more effective than lower GI
* 5-7 g/kg per day seems to be sufficient in
the majority of cases (with low energy
expenditure)
* If experience gastro-intestinal issues select
carbohydrate sources carefully - try lower
fibre intake
What are 3 important effects of the pre-competition meal (3-5 hrs before)?
- to continue to fill muscle glycogen stores after previous ex session
- to restore liver glycogen concentrations, especially morning events
- to improve endurance capacity during prolonged exercise
How much does high GI pre-competition meals increases muscle glycogen?
10-15% in 3 hrs
Low GI meal effect on muscle glycogen:
No effect. However, may promote greater rate of fat oxidation - insulin suppresses lipolysis
What are the characteristics of the pre-competition meal (3-5 hrs before)?
- Should contain relatively little fat or fibre
- Low to moderate protein
- Liquid meal supplements quickly digested option
How much CHO liquid (pre-competition) is recommended?
- ACSM: 200-300g, 3-4 hrs prior
- ISSN: 1-2 g/kg BW, 3-4 hrs prior
- IOC 1-4 g/kg BW, 1-4 hrs prior
How does CHO ingestion delay fatigue?
- prevents hypoglycaemia
- provides CHO for oxidation
- spares liver glycogen
- modifies motor output
How can CHO oxidation rates be increased from 60 g/h to 90 g/h?
Multi transport mechanisms
60g glucose / 30 g fructose
True or false
Fructose does not stimulate insulin response or elicit major changes in blood glucose
True
