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