Nutrition and Athletic Performance

Optimum Nutrition

• High in carbohydrate (55-65% of diet)• Low in fat (25-30% of diet)• Variety of foods

• 5-12 servings of grain products• 5-12 servings of vegetables and fruit• 2-6 servings of milk products• 2-4 servings of meat and alternatives

Protein

• Small percentage used to fuel activity (2-5%)• Remaining used for repair and restoring tissue• Amino acids in protein are need in certain

types of exercise– Intense activity (eg. bodybuilding)– Maintain energy stores

Carbohydrate

• Most used for aerobic and anaerobic activities• Broken down to glucose• Stored in liver and skeletal muscle as glycogen– Liver: released in bloodstream after exercise to

restore blood glucose levels– Skeletal: preferred source of energy

• Goal: eat enough carbs to replenish muscle glycogen stores

Fat• Low to moderate aerobic intensity activities• Greater the intensity, less fat is used• As athletes adapt to endurance activities,

increase in fat used as fuel source

Competition Meals

Pre-exercise Meals:• 2-6 hours BEFORE competition• Familiar to the athlete (i.e. Eat same foods)• Easily digestible carbohydrates, low in fibre (eg. Pasta, rice, fruits)

Goals:• Minimize fatigue• Adequate supply of carbohydrates • Promote glycogen synthesis

During Exercise:• Main goal: Rehydration• Find liquids contain

carbohydrates – prevent drop in blood

glucose levels– minimizing fatigue

• During events lasting more than 4 hours, small meal high in carbohydrates is recommended

Post-exercise Meals:• Main goal: rehydration and intake of carbs• High-carbohydrate diet IMMEDIATELY after

activity• Helps restore glycogen to muscle• Quick recovery

Fluid Replenishment

• Using energy during physical activity causes heat body needs to release heat to maintain temperature

• Solution: WATER

Role of water:• Transport nutrients to cells• Carry away waste products• Distributes heat throughout the body

2 mechanisms to maintain body temperature:

1.Reflex dilation of skin• Expanding blood cells in skin• Forces blood to flow & transfer heat to surface of skin

2.Sweating reflex• Activates sweat glands• Sends excess fluid to surface to evaporate

• Overall effect: cool body• Overall cost: DEHYDRATION!

• Need constant replacement of fluids to continue at peak performance

Hydrate Yourself!

Fluid Replacement

• To keep up with hydration demands, replenishment takes place before, during and after physical activity

• Content of fluid is important– In high sugar drinks like Coke level of carbohydrates is

too high and indigestion ma cause cramping and diarrhea– Tea, coffee an cola drinks act as diuretics (↑ urination)

and dehydrate body further

Before Exercise: • Begin well hydrated• 2-3 cups of fluid containing carbohydrates 2-3 hours prior to

activity• 1 cup of fluid 10 minutes prior

During Exercise:• Sports beverage containing carbohydrate if activity is longer

than 50 minutes• 6% electrolyte-carbohydrate• One ½ cup of cool fluids (10-15°C) after 10 minutes of

exercise

After Exercise:• Regained within 2 hours replenish glycogen• Can be replaced by foods high in water content (eg.

Watermelon, oranges, grapes)

Dehydration Problems

• Heat cramps– Muscles spasm or tighten due to excessive loss of

fluid & electrolytes through sweating– Symptoms: short painful muscle twitches

• Heat exhaustion– Sever condition requiring medical attention– Cumulative loss of water and weakening of body’s

ability to regulate internal temperature– Symptoms: pale, cool and clammy skin, light-

headedness, possible loss of consciousness

• Heat stroke– Very serious condition medical emergency– Complete failure of body’s heat-regulatory system– Symptoms: high body temperature, headache,

confusion, behavioural change, loss of consciousness