Nutrition Mt 2: Physical Activity And Nutrition

Front 1

Physical fitness (def.)

Back 1

Physical fitness can be defined as ones ability to perform moderate to vigorous levels of physical activity without undue fatigue and the capability of maintaining this level of activity throughout life (ACSM)

Front 2

Components of physical fitness:

Back 2

1. cardiorespiratory fitness
2. muscular strength
3. muscular endurance
4. flexibility
5. body composition
6. core strength/balance

Front 3

Differentiate between physical activity and exercise:

Back 3

Physical activity is any voluntary skeletal muscle movement

Conversely, exercise is planned, structured, using sustained or repetitive movement, and designed to improve or maintain physical fitness

Front 4

Benefits of exercise:

Back 4

*the best way to improve wellness

1. may have anti-anxiety and anti-depression effects

also decreases;
2. hypertension
3. diabetes
4. obesity
5. hyperlipidemia
6. osteoporosis
7. cardiovascular disease

additional benefits:
8. improved sleep
9. nutritional health
10. healthy body composition
11. improved bone density
12. improved immune function
13. etc. etc.

Front 5

Increased lifestyle physical activity. vs. exercise programs designed to improve physical fitness

Back 5

Increased Lifestyle:
-promotes improved health and well being
-does not necessarily improve physical fitness

Exercise programs:
-greater improvements in quality of life
-significant reductions in disease
-decrease in risk of mortality

Front 6

How much is needed to reap the health benefits:
1. increased lifestyle physical activity
2. exercise programs

Back 6

1. 60 minutes a day of moderately intense physical activity

2. 30 min/3 times a week (with HR reaching 70-85% maximum)

Front 7

How much do you need of the following for health benefits:
1. endurance activities
2. flexibility activities
3. strength activities

Back 7

1. 4-7 days a week
2. 4-7 days a week
3. 2-4 days a week

*reduced sitting for long periods of time

Front 8

Define:
1. flexibility
2. muscle strength
3. muscle endurance
4. cardiorespiratory endurance
5. power

Back 8

1. The capacity of the joints to move through a full range of motion.. the ability to bend and recover without injury

2. The ability of muscles to work against resistance

3. The ability of a muscle to contract repeatedly within a given time without becoming exhausted

4. The ability to perform large-muscle dynamic exercise of moderate-to-high intensity for prolonged periods

5. muscle strength delivered per unit of time

Front 9

Overload principle:

Back 9

Improving muscle fitness: increased physical demand on the body
-frequency
-duration
-intensity

*give body time to adapt (rate of breakdown must not exceed rate of repair and growth)

Front 10

Specificity Principle:

Back 10

Results are specific to training type/goals
-endurance
-power
-max strength
-mix

Front 11

How do our muscles grow?

Back 11

Hypertrophy = an increase in size in response to use
*cannot increase number of fibers, only the size of fibers

gains in:
-strength
-fiber size
-capilarization

Front 12

What happens if you don't use your muscles?

Back 12

Atrophy = decrease in muscle mass and size... also decrease in capilarization

Front 13

How can we ensure a reduced chance of injury when training?

Back 13

VARIETY: People need to work different muscle groups from day to day

also choose variety between stretching, weight training, and aerobic activity

Front 14

What is aerobic

Back 14

-requiring oxygen
-Aerobic activity strengthens the heart and lungs by requiring them to work harder than normal to deliver oxygen to the tissues

Front 15

Why give muscles rest?

Back 15

-It takes a day or two to replenish muscle fuel supplies and to repair wear and tear incurred through physical activity

-Periodic rest gives muscle time to adapt to an activity

-During rest, muscles build more of the equipment required to perform the activity that preceded the rest

Front 16

Adaptations in muscle due to training:

Back 16

-energy storage improves (the muscles cells of a weight lifter store extra granules of glycogen)

-connective tissue becomes stronger

-contractile proteins increase in bulk

-improved performance of a muscle

Front 17

Benefits of weight training:

Back 17

1. Helps to prevent and manage several chronic diseases (e.g. CVD)

2. Enhances psychological well-being

3. Promotes strong trunk muscles

4. Helps prevent decline in physical mobility associated w/ aging

5. Can help to maximize and maintain bone mass

6.Can emphasize either muscle strength or muscle endurance

Front 18

How do you emphasize muscle strength? muscle endurance?

Back 18

To emphasize muscle strength: high resistance and low reps

To emphasize muscle endurance: low resistance and high reps

Front 19

Benefits of cardiorespiratory training

Back 19

As cardiorespiratory endurance improves, the body delivers oxygen more efficiently

Front 20

Effects of cardiorespiratory training:

Back 20

1. The total blood volume and the number of red blood cells increase

2. the heart becomes stronger and larger

3. pulse rate falls

4. breathing becomes more efficient

5. Blood moves easily through the blood vessels

6. blood HDL increases

Front 21

Target activities to improve cariorespiratory fitness:

Back 21

1. elevate the heart rate
2. sustain for >20 minutes
3. use large muscle groups of the body

(swimming, cross-country skiing, rowing, fast walking, jogging, fast bicycling, soccer, hockey, basketball, in-line skating, lacrosse, rugby)

Front 22

Energy Sources for Physical Activity:

Back 22

ATP and Creatine phosphate = immediate energy source

carbohydrate (glucose)

fat

protein

Front 23

ATP and CP use for energy

Back 23

ATP and creatine phosphate are the immediate energy source:

*anaerobic energy production
-very small amt of ATP is available in the cells themselves
-tissues have a stock of CP... releases the phosphate and ADP + P = ATP (happens in the mitochondria)
-stocks are limited
-can supply energy for 3-15 seconds of maximal effort

Front 24

carbohydrate use for energy in moderate intensity activity

Back 24

primarily from stored glycogen in
-muscle
-liver

during moderate activities: 3-20 min
-aerobic glycolysis yields ATP

*in moderate activity for >20 min, glucose oxidation is supplemented with fatty acid oxidation

Front 25

carbohydrate for use of energy in intense activity

Back 25

lasts from 20 seconds to 3 minutes

O2 requirement is > than that delivered by the cardiovascular system:
-anaerobic glycolysis yields ATP
-may lead to build up of lactic acid

Front 26

Aerobic vs. anaerobic glycolysis:

Back 26

Aerobic:
-plenty of O2 available
-low to moderate PA (i.e. jogging)
-produces 36-38 molecules ATP per glucose (95% energy potential)
-replenishes ATP slowly
-provides energy for 2 minutes to 3 hours of work

Anaerobic:
-limited oxygen to the muscle cells
-intense physical activity (ie sprinting)
-pyruvate is converted into lactate
-produces 2 ATP per glucose (5% of energy potential)
-replenishes ATP quick
-provides energy for 30 seconds to 2 minutes
-Lactate build-up will change acidity and inhibit glycolysis enzymes

Front 27

Fat as an energy source:

Back 27

With onset of exercise, fatty acid concentration in the blood decreases

For activities >20 minutes, there is an increase in the release of fatty acids from stores (mediated by epinephrine)

Endurance training increases adaptations to enable fat burning mechanism (increase size and number of mitochondria in muscles
increase number of capillaries to supply oxygen and nutrients to muscles
increase in enzymes that support ATP synthesis)

Front 28

Protein as an energy source:

Back 28

-Not a primary source of energy
-Contributes ~ 5 - 10% of energy expenditure during both activity & rest

Factors that influence protein use during activity:
-High dietary protein and increased duration of activity can lead to increased protein utilization as fuel
-Increased intensity of activity and increased training (especially strength training) may lead to a decrease in protein utilization as fuel

Front 29

Summary for preferred fuel source:

Back 29

Duration:

8-10 seconds (extreme intensity) = ATP - CP

20 seconds- 3 minutes (very high intensity) = Anaerobic Glycolysis

3-20 minutes (high intensity) = Aerobic Glycolysis

>20 minutes (moderate intensity) = fatty acid oxidation


*NOTE: all energy sources are used to some extent at all times

Front 30

Effect of diet on physical endurance:

Back 30

Fat and Protein Diet = 57 min

Normal Mixed Diet = 114 min

High Carb Diet = 167 min

Front 31

Carbohydrate intake prior to exercise:

Back 31

Adding carbs to diet 2-4 hours prior to exercise may aid in replenishing glycogen stores

Consuming carbs, an hour before exercise may be beneficial for some athletes (this area has conflicting research)

Front 32

Gastric Distress:

Back 32

Some athletes avoid solid intake and instead prefer liquid to reduce gastric distress

Reduce fat (less than 20%) & protein (less than 15%) intakes

Front 33

Carbohydrate intake during exercise:

Back 33

Glucose replacement of 200 kcal, is useful during activities that last longer than 45 mins to an hour

Sports drinks with 6 - 10% carbohydrates (50 - 100 kcal per cup) enable athletes to perform for longer durations

Front 34

Energy Bars and Drinks:

Back 34

During endurance activities that last longer than an hour, risk of glycogen depletion

Maintain blood glucose levels to delay time to exhaustion

Front 35

Carbohydrate Loading:

Back 35

-For events lasting longer than 60-90 minutes

-Maximize glycogen stores

-Tapering of exercise while increasing CHO intake

-Water is incorporated with glycogen

-Consuming CHO during event has approximately same effect as CHO loading

Front 36

Carbohydrate intake after exercise:

Back 36

High carb meal eaten within 15min - 2 hours after exercise accelerates rate of glycogen storage by 300%, called “glycogen window”

Takes 24-48hrs to completely replenish glycogen stores

Very important for protein metabolism: prevents protein breakdown and instead promote protein retention

*foods high on the glycemic index are ideal

Front 37

Dietary Fat and Exercise:

Back 37

-Athletes requiring more than 5000 Kcal/day will find it difficult to consume adequate calories without 20-30 % of energy coming from fats

-The intensity of physical activity affects the percentage of energy contributed by fat, as it is broken down only by aerobic activity

-Duration matters: activities longer than 20 mins, will cause a significant increased in breakdown of fat molecules in the body

-Regular aerobic training, increases amount of fat burning enzymes in the muscles

Front 38

Protein and Exercise:

Back 38

Current research shows that athletes (muscle builders) require only a little more protein than what sedentary people consume

Research shows no increase in protein synthesis when an protein intake was increase beyond the recommended amounts

Athletes do not require protein powders or amino acid supplements to meet protein demands (ideal protein requirements should be met from dietary sources)

Vegetarian athletes will also be able to meet their required protein needs from dietary sources

Front 39

Protein intake after exercise:

Back 39

Athletes have an increased need for protein in their diet, as it aids in repairing and building muscle tissue after activity

Protein combined with carbohydrate makes an ideal post-exercise meal, as glycogen stores can be replenished

Recommendation for intake is 4 grams protein for every 10 grams of carbs

Front 40

Dangers of High Protein Diet:

Back 40

Increased protein intake increases diuresis, to excrete the excess nitrogen (increased risk of dehydration and loss of minerals)

In general high protein diet is high in other saturated fats and increases risk for CVD, high BP, Obesity and other related disorders (depending on your choice of proteins)

Increase intake of single amino acids, may inhibit absorption of other amino acids

Front 41

Vitamins and Minerals and athletic performance:

Back 41

Vitamins and minerals are important for energy metabolism (both during rest and during physical activity)

Slightly higher needs for vitamin E and C (antioxidant properties)

Supplements do not enhance physical performance

However, deficiencies will certainly impair performance

If the diet is adequately met and calories come from various foods then all required vitamins, minerals for metabolism are met

Front 42

Iron and physical activity:

Back 42

Iron, is vital to oxygen delivery and energy production

Female athletes may be prone to iron deficiency

This can have multiple contributing factors (sports anemia, menstrual loss…)

Supplementation should be based on blood tests, and not self-assessment

Front 43

Calcium and physical activity:

Back 43

intake is especially important for women

Front 44

Antioxidants supplements for athletes:

Back 44

~5% of oxygen from aerobic metabolism is not fully reduced, leaving free radicals and reactive oxygen species (ROS)

Resulting lipid peroxidation generates even more free radicals

Consumption of Vitamin E & C are ideal for athletes

Vitamin E, has been shown to protect against exercise-induced oxidative stress

No evidence supports consumption of Vitamin E for increased performance

Front 45

How much water should you drink post exercise?

Back 45

500ml for each pound of weight you lost

Front 46

Heat Cramps:

Back 46

-occur in skeletal muscle
-a complication of heat exhaustion
-painful muscle contraction every 1-3min
-Ensure athletes have adequate salt and fluid intake
-Exercise moderately at first in the heat
-

Front 47

Heatstroke:

Back 47

Internal body temp of > 104 degrees F

Symptoms:
-nausea
-confusion
-irritability
-poor coordination
-seizures
-coma

Front 48

Use of sports drinks:

Back 48

Recommended for activity > 60 minutes in duration

Sweat, CHO, and electrolytes lost in events <60 minutes are easily replaced by diet

For longer events, sports drinks can help maintain blood glucose level and blood volume

Over consumption of water can lead to decreased blood sodium

Front 49

Replenishing fuel during exercise:

Back 49

For events >60 minutes, consuming CHO during activity replenishes depleted glycogen stores and prevents fatigue

30 – 60 g CHO/hour, accompanied by fluid

Options:
Sports drinks
Carbohydrate gels
Energy bars
Fig cookies
Gummy bears
Jelly beans

Front 50

Electrolytes:

Back 50

electrically charged minerals: sodium, potassium, chloride, magnesium

they play a significant role in sustaining and maintaining life

They are also important in maintaining water balance

Electrolytes lost during exercise are normally gained back from normal diet

Front 51

Replenishing Electrolyes during exercise:

Back 51

For exercise >1 hour:
replacement of fluids with electrolytes may provide a slight performance advantage

Exercise >3-4 hours:
Replacing lost water & electrolytes is very important for athletes competing in events lasting longer than 3-4 hours (heavy sweating)

Front 52

Hyponatremia:

Back 52

Hyponatremia = sodium depletion from long duration profuse sweating

Occurs in endurance sport competition > 3 hours

Symptoms: similar to dehydration:
-bloating
-confusion
-seizures
-severe headache
-vomiting