Patricia A. Deuster, PhD, MPH Professor and Director Human Performance Laboratory

1
Military Sports Nutrition

• Patricia A. Deuster, PhD, MPHProfessor and
  DirectorHuman Performance Laboratory

2
Objectives

• List 3 key sports nutrition goals
• Describe issues for hydration status
• Discuss issues relating to CHO and protein intake
  after exercise
• List 4 characteristics of the ideal fluid
  replacement beverage
• Identify 2 current sports nutrition issues

3
Key Nutrition and Performance Goals

• Optimize/maintain hydration/ electrolyte status
• Maximize/maintain fuel supplies
• Maximize protein synthesis to increase lean body
  mass
• Accelerate recovery from a strenuous bout of
  activity

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Hydration Status and Guidelines
5
Human Water Needs

• Water is quintessential nutrient of life
• 50-70 of body weight is water
• 75 of lean body/skeletal muscle mass is water
• Intra- and Extra-cellular fluid compartments
• Intra 65 and Extra 35 or TBW
• 5 - 10 of TBW is turned over each day.
• NRC recommends fluid intakess approximating 1
  mL/kcal of energy expended.

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Functions of Water

• Important functions of water
• Makes up plasma, which transports and delivers
  nutrients to tissues
• Maintains body temperature and pH
• Maintains blood circulation and pressure
• Supports energy processes

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Regulation of Water Balance

• Thirst
• Daily water balance varies between 0.2 and 0.5
  each day, independent of climate
• Metabolism
• Daily turnover between 3.3 and 4.5 L/day (6 L for
  very active populations) for sedentary and active
  populations
• Requirements
• Low activity 4.5 - 8 L/day
• High Activity 6 to 12 L/day
• Losses
• 1 - 2 L/h for athletes

8
Fluid Balance
9
Dehydration and Performance
8
6
4
Weight Loss ( Body Weight)
2
2
3
gt 6
4 - 6
Impaired temperature regulation
Reduced muscular endurance
Reduced strengthReduced endurance capacityHeat
cramps
Severe heat cramps Heat strokeComaDeath
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Monitoring HydrationStatus
12 3 4 5 6 7 8 9
Urine color test for dehydration LemonadeThe
good Apple juiceThe bad TeaThe ugly
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Indices of Hydration
Body Weight Change Urine Color
Well Hydrated -1 to 1 1 or 2
Minimal Dehydration -1 to -3 3 or 4
Significant Dehydration -3 to -5 5 or 6
Serious Dehydration gt -5 gt 6
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Establishing Fluid Needs

• Estimate sweat rate or amount of fluid lost in a
  specified period of time during defined exercise
  workload
• A Body weight Pre - Post
• B Fluid intake Total volume
• C Urine volume
• Sweat loss A B - C
• Sweat rate Sweat loss/time

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Example of Fluid Needs

• Body weight
• Before 70 kg and after 67 kg
• Fluid intake 1.8 L
• Urine volume 0.7 L
• Time 2 hours or 120 min.
• Sweat loss (3 1.8 - 0.7) 4.1
• Sweat rate 4.1 L/2 hrs 2.05 L/hr

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Hydration Guidelines for Pre-Exercise

• Obtain body weight.
• Check color of urine - pale color (1 - 3)
  indicates a good hydration status.
• Drink 16 to 20 fl oz of water or sports beverage
  2 to 3 hrs before.
• Drink 8 to 12 fl oz of water 0 to 10 min before
  exercise.

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Hydration Guidelines for During Exercise

• Drink 3-8 fl oz of water every 15-20 min when
  exercising for lt 60 min
• Drink 3-8 fl oz of a beverage with CHO (5 to 8)
  and electrolytes every 15-20 min when
  exercisinggt 60 min.
• DO NOT DRINK MORE THAN 1 L or 1 Qt/hr during
  exercise.

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Hydration Guidelines for Post-Exercise

• Obtain body weight to estimate fluid losses and
  correct losses within 2 hrs.
• Rehydration is optimized when a volume equivalent
  to 150 of the body weight deficit is ingested.
• Beverage should contain water to restore
  hydration status, CHOs to replenish glycogen
  stores, and electrolytes to accelerate
  rehydration.

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US Track Field Guidelines Guidelines 3/19/2003
http//www.usatf.org/coaches/library/hydration/ In
ternational Marathon Medical Directors
Association (IMMDA) Advisory Statement on
Guidelines for Fluid Replacement During Marathon
Running, by Tim Noakes, MBChB, MD, FACSM Fluids
on Race Day, by LG Maharam, MD, FACSM Proper
Hydration for Distance Running - Identifying
Individual Fluid Needs, by DJ Casa, PhD, ATC,
FACSM
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Institute of Medicine

• Most healthy people meet hydration needs by
  letting thirst guide fluid intake.
• Healthy sedentary people in temperate climates
  91 oz (2.7 L) of water per day for women and 125
  oz (3.7 L) per day for men from all dietary
  sources.
• Very active people continually exposed to hot
  weather have daily total water needs of 6 L or
  more.

Panel on Dietary Reference Intakes for
Electrolytes and Water, Standing Committee on
the Scientific Evaluation of Dietary Reference
Intakes 2004.
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Water Requirements
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ACSM Position

• Thirst is not the best hydration indicator for
  active people and those who are exposed to heat
• Athletes should replace fluids in amounts that
  approximate sweat losses.

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Hyponatremia

• A post-race blood study on 481 participants who
  ran the 2002 Boston Marathon found that 13
  experienced hyponatremia.
• Risk factors included female gender, slower
  finishing times, and excess fluid consumption.

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Summary Hydration Status
12 3 4 5 6 7 8 9

• Fluid intake should match fluid losses.
• Urine should be monitored
• Pre-exercise urine should be lt 3
• If urine color gt 6 thendehydration is likely.
• Dehydration is NOT acceptable, whether
  involuntary or voluntary.
• Dehydration is NOT an unconditional outcome of
  exercise, or combat/military operations.
• Hyponatremia is avoidable.

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Fluid Replacement Beverages
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Optimal Fluid Replacement Beverages

• Rapid rate of gastric emptying
• Tastes good
• Provides energy substrate, if exercise gt 1 hr
• Rate of energy delivery is adequate (40 - 90 g/L
  or 36 - 76/qt)
• Provides requisite amount of sodium (0.5 to 0.7
  g/L) Need to replace body fluids gt need to
  replace electrolytes
• Absence of GI disturbances
• Best if beverages are cool (10 to 15C).

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Gastric Emptying and Solution Characteristics
Solution Characteristic
Rate of Emptying

• Volume of Solution
• Caloric Density
• Osmolarity
• Temperature
• pH

• Increases with larger volumes
• Decreases with greater density
• Decreases with hyperosmolar solutions
• Faster for cool solutions
• Slower with more acidic solutions

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Gastric Emptying

• Slow at high exercise intensities
• Same at rest and low to moderate exercise
  intensities
• Affected by fitnessthe more fit, the less
  affected by exercise
• May be enhanced by training
• Not affected by exercise duration
• Affected differently by various activities.

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Minimize GI Distress During Exercise

• Maintain hydration - hypovolemia increases
  frequency of GI complaints
• Avoid high-energy, hypertonic drinks and foods
  before (30 - 60 min) and during exercise (lt 90
  g/hour)
• Avoid high fiber foods before exercise
• Limit NSAIDs, caffeine, alcohol, and dietary
  supplements before and during exercise.

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Nutrition for Endurance and Strength Training
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Maximize Glycogen Synthesis

• Glycogen - primary fuel source during moderate to
  high intensity exercise
• Muscle glycogen repletion is slow, and can take
  24 hrs.
• Exponential relation between rate of glycogen
  resynthesis and recovery time
• Restoration of muscle glycogen most critical
  factor for recovery/ subsequent performance

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Factors Affecting Glycogen Resynthesis

• Depletion of muscle stores
• Refueling pattern - timing of ingestion
• Amount of carbohydrates consumed
• 1.0 to 1.2 g CHO/kg BW immediately after
• 1.0 to 1.2 g CHO/kg every 30 min for 5 hrs
• 6 - 10g CHO/kg BW per 24 hours
• Type of carbohydrate consumed
• Focus on high glycemic index/GIfoods post-workout

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Effects of Diet on Muscle Glycogen Content
140
120
100
High CHO
80
Low CHO
60
Muscle Glycogen
(mM/kg wet wt)
40
20
0
Day 1
Day 2
Day 3
Day 4
Time
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Glycogen and Endurance Exercise CHO vs Protein?

• Glycogen can be restored rapidly if 1.2 g/kg/hr
  of CHO are ingested immediately after and for up
  to 4 hours after exercise. van Hall G et al. J
  Appl Physiol. 2000881631-6.
• Does ingestion of CHO and AA in combination
  improve glycogen repletion?

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Muscle Glycogen Resynthesis Rate
Muscle Glycogen (nmol/kg)
Recovery Time (hr)
van Hall G et al. J Appl Physiol. 2000.
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Glycogen and Resistance Training CHO

• Resistance exercise reduces glycogen by
  approximately 30-40
• Resynthesis is slow unless energy substrates are
  provided
• Provision of CHO after exercise enhances
  resynthesis of glycogen
• Provision of protein and fat with CHO after
  exercise does not impair resynthesis.

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Comparison of Diets

• Low CHO diet (40 kcal from CHO)
• Double cheeseburger
• Medium fries
• Chocolate milkshake

• High CHO diet (70 kcal from CHO)
• 12 inch sub sandwich (lots of vegetables no
  mayo)
• 500 ml apple juice
• 250 ml chocolate milk
• banana

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Carbohydrate Snacks

• Foods supplying 50g CHO
• 500 ml Juice
• 3 Medium pieces of fruit
• 1 honey sandwich
• 2 breakfast bars
• 1 sports bar (check label)
• 1.3 bagels
• 1/2 cup dried fruit
• 1 cup white rice
• 1 baked potato

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Maximize Protein Synthesis

• Resistance exercise stimulates muscle protein
  synthesis and degradation.
• Net protein balance negativein absence of
  nutrient intake.
• Timing of pre- and post-exercise nutrient intake
  may affect rate of protein synthesis.

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Protein Balance and Resistance Exercise

• Ingestion of 40 g of essential amino acids (AA)
  resulted in positive muscle protein balance after
  resistance effort. Tipton KD et al. Am J
  Physiol. 1999276E628-34.
• Ingestion of 6 g of essential AA combined with 35
  g of CHOs at 1 and 3 hr post-exercise increased
  muscle protein balance.Rasmussen BB et al. J
  Appl Physiol. 200088386-92.

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Protein Balance and Resistance Exercise

• Ingestion of CHO and AA together was equivalent
  to the sum of giving either alone in terms of
  enhancing muscle protein balance. Miller S et
  al. Med Sci Sports Exerc. 20033544955.
• Ingestion of CHOs alone minimally improved net
  muscle protein balance after resistance exercise
  relative to placebo. Borsheim E et al. J Appl
  Physiol. 200496674-8.

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Typical Amino Acid Profile

• 6 g of essential AA in amounts designed to raise
  free intracellular amino acid pool to levels
  reflecting requirements for protein synthesis
• Amounts in mg/LHistidine 1.3 Isoleucine
  1.2Leucine 2.24 Lysine 1.86Methionine
  0.38 Phenylalanine 1.86 Threonine 1.76 Valine
  1.4

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Current Sports Nutrition Issues
42
Glycemic Index and Insulin Response Index

• Glycemic Index (GI) Ranking of food based on
  blood glucose response to reference food.
• High GI (dextrose and maltose) Evoke large
  increases in glucose.
• Carrots, raisins, corn flakes, breads, rice cakes
• Low/Moderate GI (sucrose and lactose) Evoke
  small/modest increases in glucose.
• i.e.. Yogurt, apples, dried fruit, lentils, beans
• Insulin Response Index (IRI) Ranking of food
  based on blood insulin response to same reference
  food.

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Glycemic Index of Foods

• GI gt 85
• White Bagel
• English Muffins
• Doughnut
• Raisins
• Corn Chips
• Ice Cream
• Sports Drinks

• GI lt 60
• Yogurt
• Grapefruit/Oranges
• Beans
• Peanuts
• Apples/Pears/Plums
• Milk
• Brown Rice

http//www.glycemicindex.com/
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Glycemic Responses
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CHO to Protein Ratio

• Pre- and Post-Exercise 3, 5, or 4 to 1
• Cognitive Performance Wide range in literature 1
  to 1 or 4 to 0
• Weight Loss 1.4 to 1

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Recovery Nutrition

• Provision of CHO, protein and fat to marine
  recruits immediately post exercise during basic
  training decreased muscle soreness and total
  medical visits associated with heat exhaustion,
  muscle/joint problems, and infections as compared
  to providing placebo (no energy)

Flakoll et al. JAP 200496951-956.
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Critical Re-Fueling Interval
Re-FuelingInterval
Re-FuelingInterval
Recovery
Recovery
Exercise
Exercise
Phases of Timing Nutrient Intake
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Optimizing Protein Metabolism

• Slow and fast dietary proteins
• Structure affects rate of absorption
• Absorption affects metabolic response
• Fast protein Whey
• Soluble
• Slow protein Casein
• Clots in stomach

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Fast vs. Slow Proteins

• Fast proteins increase blood AA rapidly and
  stimulate protein synthesis and oxidation
• Slow proteins promote post-prandial protein
  deposition by inhibiting breakdown
• Fast protein might be more beneficial during
  aging and wasting.

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Omega 6 Fatty Acids (Linoleic Acid)
Omega 3 Fatty Acids (Alpha-Linolenic Acid ALA)
?6-Desaturase
Gamma-linolenic acid (GLA) Evening Primrose
Oil Borage Oil Black Current Oil
Eicosapentaenoic Acid (EPA)
COX
Lipoxygenase
?5-Desaturase
Arachidonic Acid
Prostaglandins PGE1, PGE3 (Favorable)
Less Inflammatory Leukotrienes
Cyclo-oxygenase (COX)
Lipoxygenase
Docosahexaenoic Acid (DHA)
Prostaglandins (PGE2) Inflammatory
Leukotrienes
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Foods High in Omega-3 FA
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Dietary Omega 63 Ratio
1985 (251)
25
20
15
10
1909 (41)
5
0
Omega 6
Omega 3
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Omega-3 PUFA and Asthma

• Fish oil supplementation may represent a
  potentially beneficial nonpharmacologic
  intervention for asthmatic subjects with
  exercise-induced bronchospam (EIB).
• Fish oil supplementation has a markedly
  protective effect in suppressing EIB in elite
  athletes.
• Fish oil supplementation reduces airway
  narrowing, medication use, and proinflammatory
  mediator generation.
• Mickleborough TD et al. Chest 2006 29(1)39-49.

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Optimizing Post-Exercise Anabolism

• Maximize internal environment by
• Increasing insulin levels
• Increasing availability of essential amino acids
• Proposed solution
• Ingest protein hydrolysates and leucine to
  promote insulin release

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Sports Products
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Types of Fluid Replacement Beverages

• Sports and Energy Drinks both usually contain
  CHO and other performance-enhancing
  ingredients.
• Sports beverages are intended to maintain
  hydration. Optimum CHO content is between 6 and
  8 or 14 to 19 g per 8 fl oz serving.
• Energy drinks contain more energy and amino
  acids.
• Both beverages may contain any of a number of
  other ingredients.

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Brands of Beverages

• Accelerade
• All Sport
• CeraSport
• Cytomax
• Endurox R4
• Gatorade
• G-Push G1 Hydration Formula

• GU20
• Hydrade
• Metabolol Endurance
• Met-Rx ORS
• Powerade
• Pro-Hydrator
• Ultima

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Composition of Fluid Replacement Beverages
Brand Name Kcal/ 8 oz CHO (g)/ 8 oz. Type of CHO/Other
Cytomax 80 15 fructose, corn syrup, maltodextrin
Endurox R4 93 17 complex CHO, glucose, fructose
Gatorade 50 14 sucrose, glucose, fructose
POWERade 72 19 high fructose corn syrup, maltodextrin
Pro-Hydrator 0 0 No CHO - glycerol
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Sport Bars

• Developed to provide an easily accessible source
  of CHO
• Many bars provide complex proteins and may be
  high in fat.
• Vary in type and amount of energy, CHO, protein
  and fat.
• Some provide only 150 kcal andothers up to 340
  kcal
• Many contain other agents, herbs, etc

60
Brands of Sports Bars

• Atkins Advantage Bar
• Balance Bar
• Bioprotein Bar
• Clif Bar
• Detour Bar
• Gatorade Energy Bar
• GeniSoy
• Ironman Triathlon Bar
• Low Carb Keto-Bar
• Luna Bar
• Metabolift Bar

• Met-Rx
• PowerBar
• PremierNutrition Bar
• Protein Revolution Low Carb Bar
• Think Divine
• Tigers Milk
• ZonePerfect
• Sugar-Free ProteinPlus
• Ultimate Low-Carb Bar

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Military PERCs

• Performance Enhancing Ration Components
• Ration components for improving physical and
  mental performance during sustained operations
  and under all environmental conditions.
• Contain CHOs, caffeine, vitamins, and
  antioxidants.
• ERGO Drink Energy Rich, Glucose Optimized
• Primary source of CHOs (12 of drink).
• Helps replete glycogen and speed recovery.
• HooAH Bar
• Releases glucose over long period of time.
• Helps delay fatigue and extend endurance.

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CarboPack

• Contains 1 CHO rich bar and 2 - 12 oz
  CHO-electrolyte beverages in rehydration pouches
  (Not less than 75 g CHO/pack).
• Hooah Bar 40 g of CHO and 10 g protein
• Beverage meets OTSG requirements for CHO-
  Electrolyte beverages
• Sodium 55-160 mg
• Potassium 20-55 mg
• Carbohydrate 11-19 grams

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Soldier Fuel Bar

• The Hooah Bar, now known as Soldier Fuel was
  commercialized by a private company in
  collaboration with the Natick Soldier Center.
• Has been rated highly by all who taste it.
• Reformulated bar contains no trans fats.

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Sport Gels

• Designed to deliver large amounts of CHO in a
  compact and easily consumed form.
• Very slowly absorbed and must have adequate
  amounts of water to dilute and lower osmolality.
   
• Similar glycemic response when compared to liquid
  or solid foods with same amount/types of CHOs.
• Gels may be effective source of energy, but
  challenge is taking in enough fluid.

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Brands of Sport Gels

• e-Gel
• GU
• Power Gel
• Clif Shot
• Hammer Gel

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Composition of Sport Gels
Crank Sports e-Gel 82 Complex/18 Simple CHO Amino acids, vitamin B6, antioxidants,
GU Energy Gel 80 Maltodextrin/20 Fructose Amino acids, herbal blend, antioxidants, caffeine
Power Gel Maltodextrin, fructose, dextrose Amino acids, vitamins C/E, caffeine, kola nut, ginseng
Clif Shot Energy Gel 60 Complex/40 Simple CHO from rice Magnesium, caffeine (some flavors)
Hammer Gel 100 Maltodextrin Caffeine (some flavors), amino acids
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Comparison of CHOs in Gel Products
CHO
GI
IRI

• Fructose
• Honey
• Power Gel
• Sucrose
• Dextrose
• Maltodextrin

5 35 43 71 100 121
41 59 113 147 100 158
Research funded by the National Honey
BoardRichard Kreider, PhD
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Concerns with Sport Gels

• High cost alternative to other suitable foods and
  fluids.
• Some brands also contain other compounds, such as
  medium chain triglycerides (MCT oils) and
  caffeine.
• Gastrointestinal intolerance may occur due to
  concentrated CHO load.
• Should be used during training to assess
  tolerance for use during missions.
• May lead to over consumption/over-reliance on
  low-nutrient CHO sources.

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Summary

• Prior to endurance exercise, only CHO foods with
  a low GI and IRI should be ingested.
• CHO ingestion during exercise may improve
  performance in events gt 60 min.
• Combining protein with CHO following exercise may
  accelerate glycogen repletion

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Summary

• To replete glycogen stores after exercise, 1.0 -
  1.5 gram of CHO/kg body weight should be ingested
  within 15 min and repeated every 2 hr for 4 to 6
  hr.
• Ingesting protein following resistance exercise
  should enhance protein synthesis and may inhibit
  protein catabolism.
• For recovery from exercise, food with a CHO to
  protein ratio of about 4 to 1 should be ingested
  within 30 minutes after exercise.

71
Fuel Utilization and Carbohydrate Sources

• When men and women ingested 1.5 g/min of glucose
  during exercise, CHO was oxidized at similar
  rates in men and women (peak rates of 0.70 0.08
  for men and 0.65 0.06 g/min, for women).
• When short and long chain maltodextrin was
  ingested at a rate of 1.8 g/min during exercise,
  it was oxidized at about 1.0 g/min.

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Fuel Utilization and Carbohydrate Sources

• When maltodextrin and fructose are ingested at
  1.8 g/min during cycling exercise, exogenous CHO
  oxidation can reach approximately 1.5 g/min.
• When a mixture of glucose and fructose is
  ingested at high rates (2.4 g/min) during 150 min
  of cycling exercise, exogenous CHO oxidation
  rates reached peak values of approximately 1.75
  g/min.