Sports nutrition

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Sports nutrition

• Pennington Biomedical Research Center
• Nutrition for Health Professionals

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Benefits of exercise

• People who are physically active on a regular
  basis have a reduced risk of hypertension, heart
  disease, diabetes, osteoporosis, depression,
  anxiety, sleep problems, and frailty.
• Exercise reduces the risk of gaining weight and
  becoming obese, reduces the risk for stroke and,
  now we have some very good data that indicates
  that certain types of cancer may be reduced by
  exercise.

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Exercise has Specific Benefits on

• Cardiovascular health
• Increases heart strength and overall
  cardiovascular function, which decreases chance
  of developing coronary heart disease and stroke
• Helps maintain healthy blood pressure
• Can increase HDL-cholesterol and lower
  LDL-cholesterol and
  triglycerides in the blood
• Obesity
• Helps maintain lean tissue and promote loss of
  fat tissue
• Assists in better control of appetite increases
  energy expenditure
• Helps prevent or reverse development of diseases
  associated with obesity including type 2 DM, HTN,
  and CVD (even if one cant attain a more healthy
  weight)

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Exercise has Specific Benefits on

• Muscular health
• Contributes to building and maintaining muscle
  mass and muscle tone
• Diabetes
• Increases glucose uptake by muscle tissue cells
  independent of insulin action
• Contributes to energy balance, which decreases
  risk of type 2 diabetes and related complications
• Osteoporosis
• Helps strengthen bones and contributes
  to joint health

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Exercise has Specific Benefits on

• Infections
• Reduces susceptibility to respiratory and other
  infections by enhancing various functions of the
  immune system
• Cancer
• Reduces risk of colon cancer, and likely breast
  cancer
• Gastrointestinal health
• Improves peristaltic function and colonic
  mass movements
• Lessens risk for gallstones and related
  gallbladder disease

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Exercise has Specific Benefits on

• Fewer Injuries (from falls)
• Contributes to balance and agility, especially in
  older adulthood
• Psychological health
• Reduces depression, anxiety, and mental
  stress, while enhancing a sense of
  well-being and self-
  image, and improving sleep patterns

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Recommendations

• Start slowly
• Vary your workouts make it fun
• Workout with friends and others
• Set specific attainable goals and monitor
  progress
• Set aside a specific time each day for exercise
  build it into your routine, but make it
  convenient
• Reward yourself for being successful in keeping
  up with your goals
• Dont worry about occasional setbacks focus on
  the long-term benefits to your health

Experts recommend that, to help yourself stay
with an exercise program, you should
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Diet

• There is nothing unique about the optimal diet
  for a person who is in an exercise program. One
  important aspect about physical activity and its
  interaction with nutrition is that, when people
  become physically active, research shows that
  they will spontaneously eat more.
• Over time, exercised individuals will be able to
  maintain their energy balance, reducing weight
  gains that occur with aging.

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Energy Needs

• Because of the increased energy demands of
  physical activity, individuals need to eat
  a little bit more in their
  diet to maintain their body weight.
• This, in turn, means that they are spontaneously
  getting more of the other types of nutrients in
  their diet protein, vitamins, and minerals.

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Supplements

• An exercise program combined with supplemental
  protein or micronutrients has no great benefits
  over exercise alone as far as increasing aerobic
  capacity, muscle strength, and function.
• To date, there is little added benefit from the
  nutritional manipulation on performance.

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Protein Supplementation

• There is no evidence whatsoever that increasing
  protein over and above what people normally take
  in their diet will optimize the gain in muscle
  mass with exercise or optimize performance. Most
  Americans well exceed the RDA for protein each
  day anyways.
• So, for healthy men and women, adding protein
  supplements is not going to help at all.

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Protein Athletes

• Typical protein needs for athletes range from 1.2
  to 1.6 g/kg body weight.
• For endurance athletes, about 10 of energy comes
  from protein and these individuals should aim for
  the higher value.
• Untrained subjects undergoing endurance training
  increase their protein need to about
  1.0 to 1.2 g/kg/d, well above the RDA of 0.8
  g/kg body weight.

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Protein Body building

• In the initial stages of body building when a lot
  of new tissue is being built, intake should be
  around 1.8-2.0 g/kg body weight.
• This is probably due to the fact that resistance
  exercise seems to exert an anabolic effect and
  allows for better protein utilization.
• Once the desired muscle mass is achieved, protein
  intake need not exceed twice that of the RDA (
  gt 1.6 g/kg).

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Protein Older Adults

• A subset of about 20 to 25 of older men and
  women may not get the RDA for protein. For them
  (and the very frail, or with denture problems and
  poor food intake) increased protein intake is
  recommended when they are starting an exercise
  program.
• Protein should be from food sources, not from
  supplements. Milk shakes and other dairy-based
  foods can greatly help.

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Protein Toxicity

• There could be a toxicity risk when people start
  consuming too much protein (over 2.0 g/kg/d).
• An excessive load of protein represents a
  stressful stimulus for the kidney. This is even
  more of a concern as we get older, when the
  kidneys activities decrease.
• Very high protein diets will result in
  overworking the filtration system of the kidneys.

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AA Supplements

• Amino acid supplements are widely used by
  athletes. These supplements are not digested and
  absorbed in the body as readily as amino acids
  coming from food sources.
• Moreover, amino acid supplements tend to cause an
  imbalance of the amino acids already present in
  the body.

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Fuels for muscle cells
Source/System When in Use Examples of an Exercise
ATP At all times All types
Phosphocreatine (PCr) All exercises initially extreme exercise thereafter Shotput, jumping
Carbohydrate (anaerobic) High-intensity exercise, especially lasting 30 seconds to 2 minutes 200-yard (20 meter) sprint
Carbohydrate (aerobic) Exercise lasting 2 minutes to 4-5 hours the higher the intensity, the greater the use Basketball, swimming, jogging
Fat (aerobic) Exercise lasting more than a few minutes greater amounts are used at lower exercise intensities Long-distance running, long-distance cycling much of the fuel used in a brisk walk is fat
Protein (aerobic) Low quantity during all exercise moderate quantity in endurance exercise, especially when carbohydrate fuel is lacking Long-distance running
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Phosphocreatine (PCr)

• During periods of relaxation, muscles synthesize
  PCr from ATP and creatine and then store this in
  small amounts. As soon as ADP, from the breakdown
  of ATP, begins to accumulate in a contracting
  muscle, an enzyme is activated that transfers a
  high-energy Pi from PCr to ADP, thus reforming
  ATP.
• PCr ADP ? Cr ATP

Advantage of PCr It can be activated instantly
and can replenish ATP at rates fast enough to
meet the energy demands of the fastest and most
powerful sports events. Disadvantage of PCr Not
enough is made and stored in the muscle to
sustain a high rate of ATP resupply for more than
a few minutes.
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Anaerobic Pathway
Carbohydrate

• The anaerobic pathway has three major
  disadvantages
• It cant sustain ATP production for long
• Only about 5 of the energy available from
  glucose is released during glycolysis
• The rapid accumulation of lactate greatly
  increases the acidity of muscle cells
• Because high acidity inhibits the activity of key
  enzymes in glycolysis, anaerobic ATP production
  soon slows and fatigue sets in.

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Aerobic Pathway
Carbohydrate

• If there is plenty of oxygen available in muscles
  (aerobic state) and the physical activity is of
  moderate to low intensity (jogging or distance
  swimming), then the bulk of pyruvate produced by
  glycolysis is shuttled to the mitochondria and
  further metabolized into carbon dioxide and water
  in a series of reactions.
• Although the aerobic pathway supplies ATP more
  slowly than does the anaerobic pathway, it
  releases more energy.
• In addition, ATP production via the aerobic
  pathway can be sustained for hours.

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Fat Main fuel
for prolonged low-intensity exercise

• Factors that increase the rate at which muscles
  use fatty acids for energy.
• How much the particular muscle is trained
  Muscles that are highly trained contain more,
  larger mitochondria when compared to similar
  untrained muscles.
• The concentration of fatty acids released from
  adipose stores into the bloodstream
  If more is present,
  then more will be used.
• Length of exercise
  As exercise
  becomes increasingly prolonged, fat use
  predominates (especially if exercise remains at a
  low-gtmoderate aerobic rate).

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Protein Minor
fuel source, primarily for endurance exercise

• Although amino acids derived from protein are
  used to fuel muscles, their contribution is
  relatively small when compared with that of
  carbohydrate and fat.
• Only about 5 of the bodys general energy needs
  are supplied by proteins.
• However, proteins can contribute significantly to
  energy needs in endurance exercise, perhaps as
  much as 10-15, especially as glycogen stores in
  the muscle are exhausted.

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Fuel Use and Sources

• A 100-meter sprint is powered by stored ATP,
  creatine phosphate, and glycolysis of muscle
  glycogen producing lactic acid.
• A 1000-meter run is powered at first by ATP,
  creatine phosphate and glycolysis and also some
  fat oxidation.
• Marathon ATP generated equally from glycogen
  and fatty acids are used as fuel for marathons.

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Velocity versus Fuel
ATP
More Carbohydrate
More Fat
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Energy Needs

• The daily energy needs of an athlete depend on
  his/her activity factor. A high level of
  sustained activity can double the daily energy
  required for BMR and activity.
• Weight maintenance indicates adequate caloric
  intake.

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Energy Needs

• Calories are an important factor but not one to
  worry very much over because normal appetite
  regulation will enable individuals to adjust
  their intake, depending on what their energy
  expenditure dictates.
• If a person starts an exercise program, his/her
  appetite will generally increase to meet the
  body's extra needs and, in this way, the
  individual will be able to maintain weight.

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Vitamins and Minerals

• Higher energy intake generally assures greater
  intake of vitamins and minerals if sensible meals
  are consumed.
• Long distance and marathon runners may require
  iron supplementation due to breakdown of red
  blood cells during prolonged running events.

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Carbohydrate Loading
Days 1 2 3 4 5 6
Exercise Time (minutes) Rest 20 20 40 40 60
Carbohydrate (g) 600 600 600 450 450 450
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Appropriate Activities for Carbohydrate Loading

• Marathons
• Long-distance swimming
• Cross-country skiing
• 30-k runs
• Triathlons
• Soccer
• Long-distance canoe racing
• Cycling events

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Inappropriate Activities for Carbohydrate
Loading

• Football games
• 10-k runs
• Walking and hiking
• Most swimming events
• Basketball games
• Weight lifting
• Most track and field

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Fluids

• One nutrient that we don't often think about that
  is essential for a successful exercise
  programfluids! It is important to monitor the
  hydration level of the physically active person.
• Many people are dehydrated subclinically,
  especially older individuals or people who are
  exercising in heat and, in these situations,
  hydration needs go up precipitously.

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Fluids

• Active people should be encouraged to drink more
  non-alcoholic, non-caffeinated fluids when they
  become physically active.
• At least eight (8 ounce) glasses of fluids per
  day.

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Dehydration

• Athletes that depend on weight class to enter an
  event run a risk of dehydration.
• As little as 3 loss of body weight as water
  impairs performance, particularly endurance
  events.

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Normal weight

• Thirst
• Stronger thirst, vague discomfort
• Economy of movement, impatience, sleepiness,
  apathy
• Tingling in arms, feet, headache, increase in
  body temperature
• Dizziness, cyanosis, indistinct speech, mental
  confusion

0 2 4 6 8
Percent weight loss
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Normal weight

• Spastic muscles, general incapacity, delirium,
  failing renal function
• Shriveled skin, inability to swallow, sunken
  eyes, painful urination
• Cessation of urine formation, cracked skin, bare
  survival limit
• Death

10 15 20
Percent weight loss
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Exercising in Hot Climates

• Heat related illnesses include
• heat cramps, heat exhaustion, and heat stroke.
• Heat cramps are deemed the most benign. They are
  characterized by painful spasms of the skeletal
  musculature, particularly the legs. The body
  temperature is usually normal.

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Exercising in Hot Climates

• Heat exhaustion is characterized by fluid
  depletion. Patients tend to present sweating
  profusely. Symptoms include headaches, nausea,
  vomiting, dizziness, and syncope. Treatment
  includes rest, rehydration (which often needs to
  be given intravenously), and cooling.

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Exercising in Hot Climates

• Heat stroke is a life threatening emergency
  defined as a high core temperature (gt40C)
  accompanied by neurological symptoms. The
  presentation can range between a patient with
  minimal to no sweating, to a patient with profuse
  sweating.
• The patient should be moved to a cool
  environment, clothing removed and evaporative
  cooling of the skin encouraged by spraying tepid
  water over the body, while electric fans are
  directed at the patient. If available, bags of
  ice should be placed over the major vessels in
  the axillae, groin and neck or ice water baths.
• Heat stroke requires treatment in the ER.

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People who would not benefit from an exercise
program

• Those with unstable medical conditions
• Unstable angina
• Out-of-control diabetes
• Uncontrolled blood pressure
• Or patients who have experienced other serious
  medical events within the last six months

• These listed individuals should not have a
  regular exercise program until their condition
  has better stabilized. Also not beneficial for
  those immediately after a major surgery, those
  with a progressive neurological disorder, or any
  type of progressive disease state that has not
  been stabilized.

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References

• Wardlaw G., Kessel M. Perspectives in nutrition.
  5th ed. 2002.

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Pennington Biomedical Research Center

• Division of Education

• Phillip Brantley, PhD, DirectorPennington
  Biomedical Research Center
• Claude Bouchard, PhD, Executive Director
• Heli J. Roy, PhD, RD
• Shanna Lundy, BS
• Beth Kalicki

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About Our Company

• The Pennington Biomedical Research Center is a
  world-renowned nutrition research center.
•  
• Mission
• To promote healthier lives through research and
  education in nutrition and preventive medicine.
•  
• The Pennington Center has several research areas,
  including
•  
• Clinical Obesity Research
• Experimental Obesity
• Functional Foods
• Health and Performance Enhancement
• Nutrition and Chronic Diseases
• Nutrition and the Brain
• Dementia, Alzheimers and healthy aging
• Diet, exercise, weight loss and weight loss
  maintenance
•  
• The research fostered in these areas can have a
  profound impact on healthy living and on the
  prevention of common chronic diseases, such as
  heart disease, cancer, diabetes, hypertension and
  osteoporosis.
•  
• The Division of Education provides education and
  information to the scientific community and the
  public about research findings, training programs
  and research areas, and coordinates educational
  events for the public on various health issues.