Exercise Nutrition Flashcards
What is a nutrient?
Chemical compound necessary to sustain life
What are the six categories of nutrients?
Water Carbohydrates Fats Proteins Vitamins Minerals
What is the most important nutrient to consume prior to, during and after exercise?
Water
What is dehydration?
Causes hyperthermia
1% decrease in body weight
2-3% decrease can decrease performance by 30%
Most water comes from what?
Fluid intake but can also come from solid food and metabolism
Water loss occurs from what?
Evaporation of sweat and respiration
What is the rate of gastric emptying?
600-1200 ml/ hour and it increases with exercise
What are hydration influences?
Aids gastric emptying
Cool Fluids may empty faster
What happens when water absorption is increased?
A low sodium addition to water can aid in waster absorption and water retention and stimulates thirst
Why is there support for energy drinks?
Because of increased fatty acid metabolism and glycogen sparing, which increased aerobic endurance
Increased arousal and reaction time
Is there support energy expenditure with energy drinks?
Some support but the effects are small
What is glycerol?
It is used to enhance hydration status of the body (controversial)
0.5-1.0g glycerol/kg of water to maintain body water
How does glycerol work?
Establishes an osmotic gradient in blood and tissues that enhances water uptake from the gut into the blood then from blood into cells
What is osmosis?
Passage of a solvent from a less concentrated to a more concentrated solution across a semi-permeable membrane
What is water intoxication (hypoantremia)?
Consuming high volumes of water coupled with excess sodium loss in sweat resulting in a dilution of blood sodium content.
- Most likely in ultra-endurance events
- Fluid accumulates in the brain
How do you avoid hypoantremia?
Control volumes of water and use some electrolytes during rehydration
What are the different forms of carbohydrates and what are all of them broken down into?
What do muscles mostly use?**
*Monosaccharides (glucose**)* Di saccharides (sucrose) Polysaccharides (glycogen)
What is Glycemic index?
Indicates how high blood glucose is elevated over a 2 hour period following ingestion
Based on glucose
What does GI tell us?
How high your blood glucose goes
It is important to consider how long the elevation lasts
What is glycemic load?
It determines the overall effect on your blood glucose rise when you eat food.
What do you need to know to determine GL?
GL(g) = (GI/100) x net or available CHO
1) how much cho is in each food item
2) The GI of each
The higher the GL the greater the blood glucose response
What is carbohydrate loading?
Improve performance by increasing skeletal muscle glycogen concentrations above normal levels
Most effective in events lasting longer than 60 min, shorter intermittent events or events repeated several time in a day
What are the benefits of carb-loading?
Double muscle glycogen
Requires more hydration
Most beneficial when used in conjunction with a taper
Modest weight gain
What are the four procedures of carb-loading?
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What is fast carb-loading?
1) Brief bout of very high intensity exercise
2) Followed by high CHO diet for 24 hrs
3) Results in 82% increase in muscle glycogen
Nutrition considerations for pre-event
1) timing ( light 1-2hrrs, heavy 3-4hrs)
2) Consume low to mod GI
3) 3-5g of CHO/kg of BW
4) Limit fat and protein (slow digestion)
5) Stay hydrated
6) Consume some low glycemic CHO one hour before
Consideration of fat and protein intake pre-event
1) they slow digestion
2) Some are recommended especially for long endurance events
- Some glycogen sparing can occur due to fat metabolism
- Proteins can be used for energy metabolism
Consideration for nutrition during events less than 1 hour
and 1-3hrs and events greater than 3 hours
-250ml of cool water every 15-20 min
-water with 4-8% CHO and small amounts of sodium
1L/hour (250ml/15min)
-Drink every 15-30 min, CHO 4-8% concentration
sodium can be higher
Nutrition after events
Re-hydration and restoration of CHO
Best to consume CHO immediately after the event
Initially high GI and then mod GI foods
What is protein content in diet?
15% supplies athletes with ~1.5g/kg/d
30% greater than 1.5g/kg/d
20% recommended in adolescents
Are protein supplements beneficial?
for athletes that are: not eating right strict vegetarians require several hours of training/day using steroid
Is consuming protein before during or after an event beneficial?
Low protein before long endurance can be helpful
Shorter endurance no effect
Low-mod amounts after can aid in repair and gylcogen recovery
Is consuming protein before, during or after an strength event beneficial?
Shown to improve: protein synthesis reduce muscle damage stimulate anabolic steroids improve glycogen recovery
Fat nutrition
Some fat before event is used in recovery
nothing suggests that dietary fat helps in metabolic function
