Carbohydrate Everyday carbohydrate : –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 Hours 123 Food eaten Low GI (pasta) High GI (potatoes) Blood glucose 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.
Less refined carbohydrate diet Oatmeal Blood glucose Insulin Not hungry yet Lentil soup Exercise effects on insulin
Protein needs 0.8 Requirement -for average Canadian Requirement -for endurance athlete (use protein as fuel) 1.2 -1.4 Grams protein/kg body weight/day 1.4 -1.8 Requirement -for power athlete (for muscle syn) Typical Canadian diet 1.4 - 2.0 > 3
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: Nuts & seeds Avocado Olive & canola oils Legumes Fish Whole grains Saturated Fat: Chocolate, Meat, Dairy Trans Fat: Fast food Processed/baked goods 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
During 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: Top-up glycogen in liver and muscle Top-up blood glucose Increase CHO use Prevent hypoglycemia Help psychologically Can also cause gastrointestinal discomfort, avoid: 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 (200- 300g 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: –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 –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: Watch for Dehydration Reduced performance at 2% weight loss through dehydration ~1.3 kg Signs: –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 1 kg weight loss = 1 L water loss Dehydration at 1% weight loss ~1.5 lbs Need to replace 150% of loss Monitor weight: Pre exercise wt 60 Kg Weight after exercise58 Kg Fluid loss - 2 kg = 2 L H2O Need to rehydrate with 150% = 3 L
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 –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 10 minute race Snack water, water, water banana Lunch 12” turkey sub 3 orange 250 ml skim milk 1 apple water, water, water Snack 1 c fruit yogurt 2 kiwi 20 minute race Snack: water, bagel and peanut butter 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 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: 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 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