Transcript Sport Nutrition For Competitive Rowing

Sport Nutrition
For Competitive Rowing
Cristina Sutter, MHSc., BSc (Kines)
Registered Dietitian
www.satoriintegrativehealth.com
[email protected]
Performance Benefits
0-1% or negative?
24%
Sport Nutrition
75%
Healthy Diet
Supplemenents
Fuel
and Fluids
Moderation,
Food Groups,
Balance, variety,
Regular meals and snacks,
Optimal performance goals of
sport nutrition (Burke & Read, 1993)
• ensure adequate fuel stores
• prevent dehydration
• achieve and maintain appropriate lean and fat
mass;
• achieve gastro-intestinal comfort
• promote optimal adaptation and recovery
Healthy Diet
Have Regular Meals and Snacks
(Breakfast is the most important meal)
Healthy Choices
Four Food Groups
5-15
5-15
4-6
2-4
This is where
you start…….
Carbohydrate
Everyday carbohydrate :
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Total Daily Intake: 5-13 grams carb/kg/day
1-4 hours before exercise: 1-4 grams carb/kg
During practice: 1 gram carb/kg/hour
After practice: 1.2 grams carb/kg/hour until a
meal is eaten. Best to eat a meal within 2 hours.
Glycemic Index
The glycemic index is the measure of the relative increase
in blood glucose after eating 50 g of a carbohydrate food,
compared to a glucose drink.
High GI (potatoes)
Low GI (pasta)
1
Food eaten
2
Hours
3
Refined Carbohydrate Diet
(high glycemic index)
Insulin
Hunger!
snack
McSnack
snack
Less refined carbohydrate diet
Insulin
Exercise
effects on
insulin
Oatmeal
Not hungry
yet
Lentil soup
>3
Protein needs
Grams protein/kg body weight/day
1.4 -1.8
1.4 - 2.0
1.2 -1.4
0.8
Requirement
-for average
Canadian
Requirement
-for endurance
athlete (use
protein as fuel)
Requirement
-for power
athlete (for
muscle syn)
Typical
Canadian
diet
Is protein helpful during recovery?
• Doesn’t aid in fuel recovery
– Filling-up on protein could
cut appetite for carbs
• Small amounts combined with CHO may
aid muscle protein recovery
– 250 ml Chocolate milk
– 250 ml Fruit Yoghurt
Fat is important
Essential Fat:
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Nuts & seeds
Avocado
Olive & canola oils
Legumes
Fish
Whole grains
Saturated Fat:
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Chocolate, Meat, Dairy
Trans Fat:
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Fast food
Processed/baked goods
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Muffins, pies, cakes
Snacks:chips, crackers,
cookies
• Processed meats: hot
dog, bologna,
• Frozen fries, pizza pop,
chicken fingers
Fat: Too Much or Too Little?
Handout page 9
• Likely too much (of the wrong) fat:
– fast food & take-out meals
– commercially processed foods (e.g. frozen chicken,
pizza pockets, cookies, crackers, donuts, etc.)
– few vegetables or fruit
– always eats desserts
• Likely too little fat:
– no or very little meat,
– avoids egg yolks, ‘regular’ salad dressings, nuts,
avocados, cheeses, milk, butter/margarine, and all fried
foods.
– counting grams of fat in their diet
Fuels
Carbohydrate *main fuel during exercise
• maintains blood glucose
• limited body stores: glycogen in liver and muscles
• usually burned, rarely goes to fat
Fat
• body fat stores (unlimited)
• burned:
• In long slow distance, recovery
• When glycogen runs out
Protein
• body tissues (no stores)
• converted to carbohydrate for energy (not desirable)
• excess protein converted to fat
Fuel for Performance
Carbohydrate During Event...
Supplement with High Glycemic Index Carbs
during exercise, if glycogen runs out (low stores
or long/intense exercise)
• immediately (<10 min) before event can eat carbs
– adrenalin suppresses insulin response
• During event, start fueling 30 min before glycogen
depletion:
– 30-70g CHO/hr = 0.5-1g CHO/kg/hr
– 6g glucose/100ml = 400 - 1000ml/hr
What fuel are muscles burning?
• Depends on intensity:
– 90 min practice (70% CHO / 30% fat)
– Regatta (100% CHO)
• Depends on what they’ve eaten:
– Eat carb in the past few hours: at any
intensity/training (90%-100% CHO / 0-10% fat)
• This is GOOD for high intensity exercise!
Glycogen Stores
• Muscle carbohydrate (glycogen) stores last:
– 1-2 hr at 70-90 % VO2max
– 2-3 hr at 60-80% VO2max
– 30 min at 90-130% VO2max
• If carbohydrate runs-out (glycogen depletion):
• Body burns protein and fat
– Very slow fuels, can’t sustain high intensities
Outcomes of Carbohydrate Shortage
“Glycogen Depletion”
• Poor endurance performance “Hit the
wall”
• Sluggish brain activity, central fatigue
• Hypoglycemia
– Symptoms: shake, sweat, tremble, hungry, poor
concentration
– Stress response: immune system is weakened
Pre-exercise Carbohydrate
• Pre-exercise meals/snacks can:
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Top-up glycogen in liver and muscle
Top-up blood glucose
Increase CHO use
Prevent hypoglycemia
Help psychologically
• Can also cause gastrointestinal discomfort, avoid:
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Unfamiliar: select well tolerated foods only
Fibre (apples, legumes, vegetables, whole grains)
Fat
Protein
Pre-exercise Carbohydrate...
• 3 days prior to endurance event eat a high (70%)
carbohydrate diet
• 4-6 hrs before event may eat up to 5g CHO/kg (200300g carbohydrate)
– enough time to get into muscle glycogen stores
• 1-4 hours before event eat 1-4 grams CHO/kg
• 15-60 min before event avoid carbohydrate
– causes insulin response, early reliance on carbohydrate
and hypoglycemia
Carbohydrate after training
• If have less than 20 hours to recover:
– High glycemic index, immediately
– 0.7-1 gram CHO/kg/hour until meal
• If have more than 24 hours:
– 7-10 grams/kg/day works well
Put Glycemic Index to work for you
• High glycemic index great for:
– Short event
– Quick top-up <10 min. before exercise
– Quick supplement during exercise
• Over 90 minutes
– start 30 minutes before fatigue
• Drinks often most acceptable
– Quick recovery of glycogen stores (if in hurry)
Put Glycemic Index to work for you
• Low glycemic index foods great for:
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Fueling longer training
Overnight recovery
When muscle glycogen stores are full
Abating hunger for longer
Rules for Recovery Following Exercise
• You need 5 hours to recover partially,
17-24 hours to replete glycogen stores completely
• Fill your muscles first:
– Junk only fills your stomach
– You won’t want to eat the important stuff
• Until you’ve had your recovery carbohydrate and fluid,
avoid:
– Fat & excessive protein
– Too much alcohol & caffeine
Summary
• Eat plenty of carbs
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Daily (5-10 grams/Kg/day)
Before exercise (1-4 g/kg; 1-4 hours before)
During exercise (>90 minutes: 0.5 to 1 g/kg/hr)
After exercise (1 g/kg/hr up to next meal)
• Unknown if protein can benefit muscle
• Get adequate protein, BUT high protein diets:
• Enhance dehydration
• Strain kidneys
• Increase likelihood carbohydrate depletion
– Performance loss (muscles and brain)
– Immune system weakened
In general, what to eat more of?
• Fruit (fresh, dried, canned)
• Vegetables (dark colours are best)
• Whole grains (cereals, bagels, bread, crackers, pasta,
rice)
• Nuts & Seeds (not roasted)
• Beans (canned = easy)
• Yogurt, milk (chocolate is OK)
What and when?
• Before morning training
– Cereal and juice
– Yoghurt and banana
– Crackers and milk
• After morning training
– Water water water
– Bagel and peanutbutter
– Bag of cereal, juice
• At lunch
– A real lunch with fruit &
milk
• After school
– Baby Carrots
– Trail mix
• After practice
– Water water water
– Fruit bar or raisins
• Supper and snack
Fluids for Performance
Fluids: Watch for Dehydration
• Reduced performance at 2% weight loss
through dehydration ~1.3 kg
• Signs:
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small amount of dark yellow urine
reduced sweat, overheat
Stomach cramps
headache, sluggishness, reduced concentration
Fluid Before Practice or Race
• 600-1000ml 1 hr before
• 400-500ml of that within 15min before
Drink During Practice
• Large gulps are better than sipping
• 300ml up to 2L per hour
• Start with 600 ml @ 20 min, then repeat
150 ml every 20 min. during practice
• Add 1/10 tsp salt per Litre water = 0.5ml
Na/L H20
Drink After Practice or Race
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1 kg weight loss = 1 L water loss
Dehydration at 1% weight loss ~1.5 lbs
Need to replace 150% of loss
Monitor weight:
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Pre exercise wt
60 Kg
Weight after exercise
58 Kg
Fluid loss
- 2 kg = 2 L H2O
Need to rehydrate with 150% =
3L
Electrolytes
• Replacement rarely necessary during activity
– unless replace excessive sweating with copious amount
of water
– sweat loss = 1150mg Na/L sweat
• Need electrolytes: Sodium and Potassium
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At end of day
Don’t avoid salt
Drink tomato juice, V8, skim milk
Eat lots of fruit, potatoes.
Water or Sports Drink?
– For rowers, hyponatremia/water intoxication is rare
Sports drinks
• Useful for
– Pre-exercise carb top-up
– Extra carb for long workouts (>90 min)
• Not so good
– For recovery, require B vitamins to process carbohydrate
What does a Training day look like?
Breakfast
1 bowl (400 ml) cereal
with skim milk
2 pieces toast
4Tbsp Peanut butter
1 orange
90 rowing practice: water, water, water
Snack
water, water, water
banana
Lunch
12” turkey sub
2 cookies
3 carrots, celery
250 ml skim milk
1 apple
water, water, water
Snack
1 c fruit yogurt
2 kiwi
* 60 minute dryland training: water, water
Supper
500 ml rice
veg/meat stir fry
bowl ice cream
What does a Competition day look like?
Breakfast
1 bowl (400 ml) cereal
with skim milk
2 pieces toast
250 ml orange juice
Snack
1 c fruit yogurt
2 kiwi
20 minute race
10 minute race
Snack: water, bagel and peanut butter
Snack
water, water, water
banana
Lunch
12” turkey sub
3 orange
250 ml skim milk
1 apple
water, water, water
Supper
500 ml rice
veg/meat stir fry
bowl ice cream
water, water, water
Dessert: chips, pop
Weight Cutting
• lose 5% body weight in 24 hours
• weigh-in can be 2 to 20 hours pre-event;
single or repeated
• methods include: fluid restriction, rubber suits,
saunas, exercise, laxatives, vomiting, spitting,
diuretics
Effects of Weight Cutting
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Recovery is variable, 21% in 1 hour to 42% in 3-5 hours
Recovers in 5 - 24 hrs with rehydration + 4gcho/kg
Reduces muscle endurance and strength
Reduced anaerobic performance, lactic acid build up
Does not recover with Rehydration:
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Reduced aerobic performance: hypovolemia, increase core
temp, decrease cardiac output, VO2 max
Reduce muscle glycogen stores, if low carbohydrate intake
Weight Cutting
Recommendations
 performance declines if wt loss >4% and
have less than 5 hours to recover
 if have 5+ hours: 4 - 8% loss rapid will be
OK for strength and anaerobic
• Sauna does not reduce performance as
much as active dehydration
• high CHO diet during low Calorie phase
– 4 g CHO/kg (65-70% CHO), 1.6g prot /kg
Gradual Weight Loss
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Over many weeks
Does not reduce vo2max
Is it possible? Is athlete over-fat? Genetically doomed?
Look for ‘nice’ but not ‘necessary’ foods in diet.
Leave in a few treats.
• Look for ways to burn extra energy
• To avoid glycogen depletion if diet is <2200 cal/day,
then have high carb foods
Weight gain in athletes
 Most important nutritional factor is energy,
especially carbohydrate
 Need overload, intensity, progression and
recovery
• Recovery: muscle protein synthesis:
• reduced during and immediately after training
• CHO (1 gram/kg/hour) can increase synthesis. Benefits of
amino acids at this point uncertain.
• Need >24 hours recovery between sessions to
maximize gains
Supplements
• Are you willing to pay ?
– for something that might…
• improve performance
• make performance worse
• The Canadian government permits the sale of sports
supplements
That have no effect at enhancing performance.
That are not proven to be safe.
That can claim to do something they do not do.
That can be contaminated with other chemicals.
Supplement manufacturers can put any substance in a jar
and sell it as something else.
Caffeine
• improve performance for 5 min and endurance events
• CNS, skeletal muscle, lipolytic effects, reduce perceived
exertion
• Does not affect hydration or thermoregulation
• 3-9 mg/kg body weight = 6-7 cups coffee
– increase performance without exceeding IOC limit of 12 mcg/ml
urine
• Non-responders (untrained, nondrinkers)
• Kola nut, Guarana
• s/e: anxiety, inability to focus, GI discomfort, arrhythmia
Creatine
 Helps maintain repetitions in high-intensity, repetitive,
short-term (6 -30 sec) exercise with limited recovery time
(20 sec - 5 min) between bouts
 No effect on activities over 30 sec.
• Increases [PCr] in muscle of responders (those with
initially low levels);
• Side effects: 1 kg water weight gain, muscle cramps and
strains
• ACSM advises athletes under 18 years not to use it
Whey
• Highest quality protein
– Reduces daily total
protein requirements
• Provides amino acids
– that will be burned
as fuel if eat too many!
• No iron, Mg, Zn or B
vitamins
Glutamine
• Most abundant amino acid in body:
• Claims:
– Prevent muscle loss, boost growth & repair
– Increase immune system function
– Improve alertness (GABA), antioxidant precursor (GSH), burns
fat, etc.
 Plasma levels fall with acute exercise bouts over-training
 Supplements reduced respiratory infections in athletes (Castell, 1996)
 None able to replicate
Glucosamine Sulfate
• Suggested to:
– Stimulate cartilage cell
growth
– Reduce inflammation
• Little NA research
– Unfundable
• Others have found
effective:
– Therapeutic use
– Injectable forms