Fitness: Physical Activity, Nutrients, and Body Adaptations

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Fitness Physical Activity, Nutrients, and Body
Adaptations

• Chapter 14

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Fitness

• Depends on physical activity and exercise
• Regular physical activity
• Promotes health
• Reduces risk of developing many diseases
• Heart disease
• Cancer
• Stroke
• Diabetes
• Hypertension

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Benefits of Fitness

• Restful sleep
• Nutritional health
• Optimal body composition
• Optimal bone density
• Resistance to infectious diseases
• Low incidence of anxiety depression

• Low risk for some types of cancer
• Strong circulation lung function
• Low risk of cardio-vascular disease
• Low risk of type 2 diabetes
• Strong self image

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Benefits of Fitness

• Physical Activity Guidelines for Americans
• Minimum amount of aerobic physical activity
• http//www.health.gov/paguidelines/ fact
  sheetprof.aspx
• Intensity of activity
• Extensive health benefits
• Develop and maintain fitness
• Cardiorespiratory endurance
• Body composition
• Strength flexibility

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Fitness and Mortality
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Physical Activity Pyramid
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Guidelines for Physical Fitness from American
College of Sports Medicine
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Developing Fitness

• Goals
• Meet everyday demands of life
• Reasonable body weight body composition
• Components
• Flexibility- freely moving joints, less risk of
  injury
• Muscle strength and endurance- longer, harder
  without fatigue
• Cardiorespiratory endurance

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Developing Fitness

• Principles of conditioning (physical effect of
  training)
• Progressive overload principle
• Frequency more often
• More intensity
• Longer duration
• Bodys adaptation to physical activity
• Hypertrophy vs. atrophy
• Work different muscle groups from day to day
• Make sure it is safe to start a program
• Progress slowly
• Alternate muscle groups from day to day

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Build Fitness Minimize Injuries

• Be active all week
• Use proper equipment and attire
• Use proper form (body mechanics)
• Include warm-up and cool-down activities
• Challenge your strength and endurance a few times
  a week
• Pay attention to body signals
• Work out wisely

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Cardiorespiratory Endurance

• Length of time a person can remain active with an
  elevated heart rate
• Enhances capacity of heart, lungs, and blood
• Oxygen Delivery
• Aerobic
• VO2 max is maximal O2 uptake, THE measure of
  Cardiorespiratory fitness
• Waste Removal
• Brain and body benefit from more O2

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Target Heart Rate
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Cardiorespiratory Endurance / Conditioning

• Aerobic workouts improve heart and lung
  activities
• Cardiac output increases
• Enhanced oxygen delivery
• Increases blood volume per heartbeat (stroke
  volume)
• Slower resting heart rate
• Breathing is more efficient
• Circulation improves
• Blood pressure falls

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Cardiorespiratory Endurance and Conditioning

• Cardiorespiratory conditioning
• Activity must be sustained for 20 minutes or more
• Must use most of large-muscle groups
• Intensity must elevate heart rate
• Perceived effort
• Still able to talk comfortably

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Delivery of Oxygen by the Heart Lungs to the
Muscles
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Air (O2, CO2), other gases
The respiratory system delivers oxygen to the
blood.
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O2
CO2
CO2
O2
The circulatory system carries oxygenated blood
throughout the body.
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O2
CO2
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The blood carries the carbon dioxide back to the
lungs.
O2
CO2
The muscles and other tissues obtain oxygen from
the blood and release carbon dioxide into it.
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Cardiorespiratory Endurance

• Muscle conditioning
• Fit muscles use oxygen efficiently
• Reduces hearts workload
• Burns fat longer
• Balanced fitness program
• Level of intensity varies
• Can exercise at up to 90 of max. heart rate
• Activities you enjoy doing
• Addresses all aspects of fitness

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Resistance Training

• Purpose
• Build muscle mass
• Develop and maintain muscle strength, muscle
  power, and muscle endurance
• Benefits for prevention of chronic diseases
• Maximize and maintain bone mass
• Improve posture reduce risk of back injury
• Strength vs. power vs. endurance

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Nutrition and Exercise

• CHO and fat as fuel
• Protein to maintain and build LBM
• Vitamins minerals to support energy metabolism
  and tissue building
• Water to distribute the fuels and dissipate heat
  and wastes

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Energy Systems and Fuels to Support Activity

• Adenosine triphosphate (ATP)
• Small amounts in all body tissues all the time
• Delivers energy instantly
• Driving chemical force for muscle contraction
• When ATP is split, energy is released as
• Mechanical movement
• Heat

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Energy Systems and Fuels to Support Activity

• Creatine phosphate (CP)
• Stored in the muscles
• Employed before ATP pools dwindle
• Split anaerobically to release phosphate to
  replenish ATP supplies
• CP supplies last 10 sec. for fast energy
  (100-meter dash)
• CP reformed from P in ATP post-exercise, during
  rest

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Energy Systems and Fuels to Support Activity

• Energy-yielding nutrients
• Prolonged demands of sustained activity require
  continual ATP
• Breakdown of CHO, fat, protein produces ATP
• Muscles use a mixture of these fuels
• Factors influencing fuel use
• Diet, intensity duration of activity, training
• Anaerobic activities glucose
• Endurance activities fats

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Fuels Used for Activities of Different
Intensities Durations
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Split second energy surge to lift the barbells
involves anaerobic work.
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Sustained muscular efforts involve aerobic work
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Moderate to high-intensity exercise uses some fat
but more glucose for fuel.
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Low to moderate-intensity exercise that can be
sustained for more than 20 min uses some glucose
but more fat for fuel.
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Glucose Use During Physical Activity

• Exertion
• Liver breaks down glycogen
• Releases glucose into bloodstream
• Muscles use serum glucose and stored glycogen
• Muscle fatigue when glycogen is depleted
• Glycogen storage 2000 kcal of energy
• Intensity of activity impacts how long glycogen
  will last
• Moderate exercise uses glycogen slowly and fatty
  acids / glucose as well

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The Effect of Diet on Physical Endurance
Maximum endurance time
Fat and protein diet
57 min
Normal mixed diet
114 min
High-carbohydrate diet
167 min
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Glucose Use During Physical Activity

• Lactate
• Glycolysis rate exceeds capacity of mitochondria
  to accept H for ETC
• Accumulating pyruvate is converted to lactate
• Recent news Lactate in muscles does not cause
  fatigue/soreness
• Lactate leaves muscle and travels to liver
• Liver enzymes convert lactate back into glucose
  to return to the muscles
• Cori cycle

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Glucose Use During Physical Activity

• Duration of activity affects glycogen use
• First 20 minutes or so of moderate activity uses
  mostly glycogen
• Then liver gives up its glycogen
• After 20 minutes, fat starts to displace glycogen
  as fuel
• Eventual glucose depletion
• Nervous system function declines
• Athlete hits the wall

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Guidelines to Maximize Glucose Supply

• Eat high-carbohydrate diet (70) all
  the time
• Drink glucose or sugar-sweetened drinks during
  exercise
• Eat carbohydrate-rich food, at least 60 g. CHO
  immediately after activity
• Train the muscles to store as much glycogen as
  possible

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Glucose Use During Physical Activity

• Glucose during activity
• Foods and beverages to be consumed during
  activity
• 30 to 60 grams of carbohydrate per hour during
  prolonged events (all-day hike)
• Glucose after activity
• Enlarges glycogen stores
• Best within 2 hours of activity
• High glycemic index better

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Glucose Use During Physical Activity

• Training affects glycogen storage
• Adaptation to continual hard work
• Conditioned muscles
• Rely less on glycogen
• Rely more on fat for energy
• Trained muscles use oxygen more efficiently
• Have more mitochondria

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Fat Use During Physical Activity

• High-fat, low-carbohydrate diets impair
  performance
• Smaller glycogen stores
• Some adaptation from more fat than CHO
• May experience greater fatigue, higher perception
  of difficulty level
• Sports nutrition experts recommend 20 to 35 of
  energy from fat
• Body fat stores are another matter

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Stored Fat Use During Physical Activity

• Fat is liberated from internal fat stores and fat
  under the skin
• Areas with most to spare, donate the most
• Fatty acids released into blood not muscles being
  used
• Blood delivers amount of fat each muscle needs
• One arm can be stronger but both arms store the
  same fat
• Body fat is essential (remember body composition
  ranges from Ch. 8)

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Stored Fat Use During Physical Activity

• Strength/resistance training tone muscles under
  the fat
• Duration of activity
• Epinephrine signals fat cells to break down their
  TG and release fatty acids into blood
• Sustained, moderate activity raises serum TG and
  continues to use TG for fuel for hours later
• Intensity of activity
• As intensity increases, less and less fat used.
  Are you too out of breath? Less fat is being
  burned.
• Training (repeated aerobic activity)
• More use of fat for fuel instead of glucose
• More and larger mitochondria, stronger
  heart/lungs

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Fat breakdown comes only from aerobic
metabolism.
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Protein Use During Physical Activity and
Between Times

• Protein not a major fuel for physical activity
• Used to build muscle and other lean tissue
  between exercise times
• To some extent to fuel activity
• Protein is handled differently during activity
  and rest

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Protein Used in Muscle Building

• Synthesis of body proteins suppressed during
  activity, accelerates during hours of recovery
• Repeated activity with slight overload
• enhances muscle protein synthesis
• High-quality protein consumption
• Exercise signals DNA and RNA to synthesize
  protein
• Weight training can add 1 oz muscle/day

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Protein Used as Fuel

• Muscles speed up their use of amino acids as fuel
  during an activity
• 10 of total fuel during activity and rest
• Diet adequate in energy and rich in carbohydrate
  spare protein
• Intensity and duration
• Protein needs are higher for endurance and
  strength athletes
• 1.2 - 1.7 g/kg/d protein for athletes

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Protein Use During Physical Activity and
Between Times

• Training affects protein use
• Higher degree of training, less protein used
  during activity
• Protein recommendations
• Needs are greater for athletes in training
• Need adequate carbohydrate intake

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Recommended Protein Intakes for Athletes
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Vitamins and Minerals to Support Physical
Activity

• Roles in supporting activity
• Assist in releasing energy from fuels
• Transport oxygen
• Supplements in general
• Do not enhance performance of
  well-nourished people
• Deficiencies impede performance
• Potential for deficiency by athlete who is
  confined to a weight range

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Vitamins and Minerals to Support Physical
Activity

• Vitamin E
• Prolonged, high-intensity activity
• Increases free radical production
• Free radicals generated during exercise may
  stimulate anti-oxidants in a beneficial way.
• Food sources best

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Vitamins and Minerals to Support Physical
Activity

• Iron
• Deficiency particularly common among active young
  women
• Vegetarian athletes most vulnerable
• Iron-deficiency anemia
• Impairs performance
• Sports anemia- temp. low Hgb
• Adaptive, temporary response
• Recommendations for athletes- get a complete
  blood count (CBC)

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Dont forget Water is a nutrient
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Fluids and Electrolytes to Support Activity

• Water loss
• Sweating and breathing
• Dehydration risk
• Temperature regulation
• Hyperthermia- esp. in humidity
• Heat stroke prevention
• Symptoms- nausea, dizziness, clumsiness, hot dry
  skin, confusion
• Hypothermia- long race on cold day
• Symptoms- shivering, euphoria?apathy

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Fluids and Electrolytes to Support Activity

• Fluid replacement via hydration
• Hydrate before activity
• Drink extra fluid in the days before event
• Rehydrate during and after activity
• Fluids for everyday, active people
• Plain, cool water
• Fluids for endurance athletes
• Carbohydrate-containing beverages

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Hydration Schedule for Physical Activity
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Fluids and Electrolytes to Support Activity

• Electrolyte losses and replacement- Na,
  K, Cl-, Mg2
• Losses occur with sweat
• Greatest in beginners
• Replacement
• Regular foods or sports drinks
• Hyponatremia
• Loss of body sodium accompanied by excessive
  liquid consumption

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Fluids and Electrolytes to Support Activity

• Sports drinks
• Hydration is critical to optimal performance
• Water is best for most people
• Sport drinks offer the following
• Fluid
• Glucose
• Sodium and other electrolytes
• Good taste

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Fluids and Electrolytes to Support Activity

• Enhanced water
• Lightly flavored
• Carbohydrates and electrolytes
• Caffeine
• Excesses can hinder performance
• Potentially danger in speeding heart rate
• Alcohol
• Negative effects

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Diets for Physically Active People

• Water
• Thirst is a late signal of need
• Nutrient density
• Vitamins, minerals, and energy
• Carbohydrates
• Pregame super high-carb meal
• Intensive training
• Protein

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Diets for Physically Active People

• Meals before and after competition
• No single food improves skill, speed, or
  strength, but favorite food is good for psyche
• 125 g protein/d, 3000 kcal/d
• Pregame meal
• 300-800 kcal, 3 hrs prior to competition
• Postgame meal
• High-carbohydrate, moderate protein, low-fat

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Athletes Meal Selections

Breakfast 1 c shredded wheat with low-fat milk
and banana 2 slices whole-wheat toast with jelly,
1.5 cups orange juice
Lunch 2 turkey sandwiches 1 1/2 c low-fat milk,
large bunch of grapes
Snack 3 c plain popcorn, a smoothie made from 1
1/2 c apple juice 1 1 / 2 frozen banana
Dinner Salad 1 c spinach, carrots, and mushrooms
with 1/2 c garbanzo beans, 1 tbs sunflower seeds,
and 1 tbs ranch salad dressing 1 c spaghetti with
meat sauce 1 c green beans 1 corn on the cob 2
slices Italian bread 4 tsp butter 1 piece angel
food cake with fresh strawberries and whipping
cream 1 c low-fat milk
Total kcal about 3000
63 kcal from carbohydrate 22 kcal from fat 15
kcal from protein
All vitamin and mineral intakes exceed the RDA
for both men and women.
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High-carbohydrate pregame meals
300-kcalorie meal 1 large apple 4 saltine
crackers 1 1/2 tbs reduced-fat peanut butter
500-kcalorie meal 1 large whole-wheat bagel 2
tbs jelly1 1/2 c low-fat milk
750-kcalorie meal 1 large baked potato2 tsp
margarine1 c steamed broccoli1 c mixed carrots
and green peas 5 vanilla wafers1 1/2 c apple or
pineapple juice
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Highlight 14

• Supplements as Ergogenic Aids

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Ergogenic Aids

• For most substances, research does not support
  claims
• Some supplements are contaminated
• Health risks
• Difficult to distinguish valid claims from bogus
  ones
• Research findings presented out of context
• Facts are often exaggerated and twisted

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Dietary Supplements

• Carnitine
• Promoted as fat burner
• Facilitates transfer of fatty acids across
  mitochondrial membrane
• Good sources
• Chromium picolinate
• Essential trace mineral
• Involved in carbohydrate lipid metabolism
• Food sources

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Dietary Supplements

• Complete nutrition supplements
• Fall short of claims
• Creatine
• Advertised as enhancing stores of CP in muscles
• Performance enhancement
• Safety is under question
• Side effect of weight gain

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Dietary Supplements

• Conjugated linoleic acid (CLA)
• Naturally occurring polyunsaturated fatty acids
• Effect of CLA supplements on body composition
• Caffeine
• Benefits
• Adverse effects

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Hormonal Supplements

• Anabolic steroids
• Derived from male sex hormone testosterone
• Development of male characteristics
• Lean body mass
• Use is banned
• Risks associated with use
• Herbal alternatives
• Natural does not mean harmless

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Hormonal Supplements

• DHEA and androstenedione
• Hormones made in the adrenal glands
• Precursors for testosterone
• Short-term side effects
• Long-term effects
• Human growth hormone (hGH)
• Acromegaly
• Other effects