Nutrition 14: exercise

Stored ATP

A small amount of ATP is stored in muscles Used for first few seconds of exercise

Vitamins/Minerals and Exercise

A well-balanced diet should generally be sufficient for most needs No benefit in taking immediately before an event -Requires hours to days to be processed and used

In liver

Available to whole body Most glycogen is stored here

Eating after exercise

Carbs improve glycogen stores Glycogen storage rate is increased for hours after exercise High glycemic index foods may increase storage

Moderate-intensity

Conversation is possible, but not continuously

Repeated exercise

Decreases the amount of protein used during activity

Fluids and Exercise During endurance training

Drink sports drinks -Replaces water -Contains electrolytes that are lost -Replenishes some sodium Replace lost sodium -Sodium can be depleted after prolonged activity -Eating pretzels or something salty is recommended

For Competitive Athletes

Eat 3-4h before a competition -Gives time for stomach to empty Consume 300-800 kcal Carb rich foods should be chosen Should be low in fat, protein, fiber -Fat, protein are not the most needed nutrients -Fiber can cause discomfort

Short duration

First 10 min: muscle glycogen stores are used 10-20 min: liver glycogen starts to be used After 20 min: lipids used for energy more than glucose -Liver and muscle glycogen stores continue to be used

Long duration

First 20 min: fatty acids in blood are used After 20 min: stored fatty acids are used Stored fats become the major energy source

Fluids and Exercise

For short and moderate duration -Water is best --Rapidly enters tissues --Cools body

Glucose/Glycogen and Exercise

Glycogen is broken down to provide glucose -Glucose provides energy during exercise -Glycogen storage is limited -Glycogen is stored --In liver --In muscles Used for high intensity, short duration High intensity -Oxygen is not sufficient for lipid use --All oxygen is used to produce energy from carbs --Carbs may be used almost exclusively --Can't be sustained long due to limited glycogen supply

Repeated exercise promotes

Greater glycogen storage in muscles Greater fat usage during exercise

Best Diet for Prolonged Exercise?

High carb diets aid endurance more than a high lipid diet or a mixed diet

Exercise

Intensity affects types of energy molecules used during exercise

Energy use

Mainly lipids and carbs -Lipids are largest contributor Minimal protein

Low-intensity

Mildly increases breathing, sweating, and heart rate Having a conversation is easy

Repeated exercise

Muscles burn more fat Heart and lungs deliver more oxygen -Allows more fat to be used

Spot Reducing

Performing specific exercises to reduce fat in a certain area -Does not work -More fat is used from areas containing more fat --Fat is released into the blood --Energy becomes available to entire body --Muscles do not use fat around them specifically

Strength training

Protein used to build muscle Not used for energy Modest increase of protein intake can be helpful -Protein intake often does not need to be increased

Energy sources during exercise

Stored ATP Glucose/glycogen Fat Protein

High-intensity

Talking is difficult while exercising

In muscles

Used for each particular muscle Allows quick energy usage by muscles Most glycogen stored here

Fat for energy

Used for moderate intensity, long duration, repeated exercise Moderate intensity -Oxygen is needed to burn fat --Lower fat percent burned in high intensity exercise --Oxygen used for glucose in high intensity exercise

Protein and Exercise

Used in small amounts during exercise -Needed for bodily functions and structures Low carbs = more proteins used -Only proteins and carbs are used anaerobically -Low carbs = proteins needed to provide energy Used in long duration exercise and strength training Long duration --Glycogen stores are used up --Proteins must be used

Carbohydrate loading/glycogen loading

an exercise and carbohydrate regimen designed to maximize muscle glycogen levels -Continuous, long duration athletes may benefit --Ex: marathon, cross-country skiing --Baseball, football, 10k runs don't seem to benefit

Lipid storage

is almost unlimited Storage beneath skin -Available to whole body Storage around muscles -Available to whole body