Upload
levana
View
28
Download
3
Tags:
Embed Size (px)
DESCRIPTION
Nutritional Considerations for Intense Training and Sports Competition. Chapter 8 Part 2. Carbohydrates During Exercise. Competition less than 30 min 5,000 meter ( ~ 12 min) 10,000 meter ( ~ 26 min ) Not necessary. Carbohydrates During Exercise. Prevention of hypoglycemia - PowerPoint PPT Presentation
Citation preview
Nutritional Considerations for Intense Training and
Sports CompetitionChapter 8 Part 2
Competition less than 30 min◦ 5,000 meter (~ 12 min)◦ 10,000 meter (~ 26 min)
Not necessary
Carbohydrates During Exercise
Prevention of hypoglycemia◦ Central nervous system effects
Dizziness Nausea Disorientation
Carbohydrates During Exercise
High intensity aerobic exercise◦ 1 hour
Decreases liver glycogen 55%
◦ 2 hours Depletes liver and muscle glycogen
Intermittent sports◦ Up to 5 hours
Carbohydrates During Exercise
Allows for a greater intensity during prolonged activities About 60 g of carbohydrates each hour benefits:
High-intensity, long-duration aerobic exercise◦ Not needed for repetitive short bouts of near-
maximal effort However, it won’t hurt if you like to drink CHO drinks
during such exercise
Carbohydrates During Exercise
Why? Spares muscle glycogen Helps maintain blood glucose levels
Improves mental and physical performance◦ Should only be glucose
Fructose causes significant GI distress
Carbohydrates During Exercise
CHO ingestion - Williams (1989)◦ Run a fixed distance in 2 hours
1 liter glucose polymer No difference in total distance covered Running speed greater over last 30 min
Carbohydrates During Exercise
Ergogenic Advantage
Ingested CHO available for oxidation◦ How much CHO should be consumed?
Rate of oxidation of exogenous CHO = 1 g/min 30-60 g/h (Coyle, 1991)
◦ When should CHO be consumed? Early and often
Every 15 minutes from the beginning of exercise You may not need it early on, but you do need the fluid
and it’s not gonna hurt you
Carbohydrates During Exercise
Fluid replacement ◦ Electrolyte concentrations
Sodium Potassium Calcium Magnesium Chloride
Carbohydrates During Exercise
The ideal hydration solution contains between 5% and 8% carbohydrates. Too high, slow gastric emptying, causes diarrhea
Maintains blood glucose during prolonged exercise Allows CHO metabolism to continue at a time
when hypoglycemia would normally occur
Carbohydrate-Electrolyte Beverages
Fluid choices for endurance events◦ Water
No CHO◦ Sports drinks (5-8% CHO + electrolytes)
600-1000 mL Ideal
◦ Soft drink (11% CHO) 500 mL Too much sugar, not enough fluid and too much carbonation
◦ Fruit juices (8-12% CHO) 500 mL Too much sugar, not enough fluid
◦ Sports gel (60-70% CHO) (1-2 gels)
Carbohydrates During Exercise
Non-endurance sports (< 30 min)◦ Start well hydrated◦ Replace fluid as soon as possible after
competition◦ Fluids ingested during event won’t help
performance
Carbohydrates During Exercise
Events of 30-60 min◦ Begin well hydrated◦ Use fluid replacement plan from training◦ Cool beverage (15-20oC) with or without CHO◦ Fluids likely won’t help, but they may be of
psychological benefit
Carbohydrates During Exercise
Events of 1-3 h◦ Begin well hydrated◦ Use fluid replacement use in training
Drink as much as is practical◦ Cool beverage (15-20oC) with CHO◦ Begin ingesting fluid early◦ Plan to consume 30-60 g CHO/h of exercise
Again, every 15 min, 250 ml of fluid
Carbohydrates During Exercise
Events greater than 3 h◦ Begin exercise well hydrated◦ Use fluid replacement plan from training◦ Cool beverage (15-20oC) with CHO
Change flavors◦ Start ingesting early during exercise◦ Plan to consume 30-60 g/h ◦ Plan for sodium replacement (most drinks have
sodium in them◦ Plan for solid food as time goes on
Carbohydrates During Exercise
Foods (50 g CHO)◦ Bananas (2-3)◦ Jelly beans (50 g)◦ Jam sandwich (2 slices bread, 4 t jam)◦ Chocolate bar (1-2)◦ Breakfast bar (1-2)◦ Sports bars (1-2)
Carbohydrates During Exercise
Multiple daily events Team sport tournaments Goals
◦ Restore muscle and liver glycogen◦ Replacement of fluid/electrolytes lost in sweat◦ Regeneration and repair damage caused by
exercise
Recovery
Should include simple and complex carbohydrates Simple: Fruits, juices, lemonade, etc. Complex: Rice, potatoes, pasta, etc.
Single large meal or small frequent meals will replenish glycogen stores.
Should be consumed as soon as possible after the activity
50-75 g CHO ◦ Every 15 min◦ Every 2 h (500-700 g)
Carbohydrates after Exercise
Factors affecting Absorption/Emptying