+

Sports NutritionFSHN 185 Spring 2013Joy GallowayGraduate Student of Nutrition Science

+

http://www.youtube.com/watch?v=IucEW2zSzCQ

+Overview of Sports Nutrition

What makes a person fit?How do anaerobic and aerobic metabolism

differ?What are special nutritional needs of athletes?What are ergogenic aids? What are physical activity recommendations?

+What Makes a Person “FIT”?Fitness = a set of attributes related to the ability to perform routine physical activities without undue fatigue

2012 USA Men’s Swim Team

+Some Health Benefits of FitnessPhysical: Reduced Risk of Chronic

Disease & Mortality (CVD, T2 Diabetes, Some Cancers & Joint Disorders)

Psychological: Improves Mood, Self-Esteem, & Overall Well-Being

+

Components of Fitnesso Body Compositiono Flexibilityo Cardiorespiratory Enduranceo Muscle Strength & Endurance

+Components of Fitness:Body Composition

+Components of Fitness:Flexibility

Range of motion—How far can you bend and stretch your muscles & ligaments?

+Components of Fitness:Cardiorespiratory Endurance

Ability to use oxygen Measured by aerobic

capacity (“VO2 Max”) Enhanced by aerobic

exercise Decreases resting

heart rate / improves cardiovascular efficiency

+Cardiorespiratory EnduranceAerobic Capacity

VO2 Max = mL/kg/min Oxygen the body can use to make ATP

Is also related to #RBC’s in body & iron status

+Aerobic CapacityVO2 Max Values

+Components of Fitness:Muscular Strength & EnduranceMuscular strength: force exertedMuscular endurance: ability to maintain

activities requiring strengthHypertrophy = growthAtrophy = loss…Events requiring Muscular Strength?

…Events requiring Muscular Endurance?

+Aerobic vs Anaerobic MetabolismHow Do They Differ?What Does This Mean Nutritionally??

Aerobic Anaerobic

+Anaerobic vs Aerobic MetabolismAmount of ATP

+Exercise Duration & Fuel Use

+Aerobic Metabolism

Occurs in mitochondria of cell Mitochondria increase in number and size with

training!

Requires oxygen Can utilize fatty acids, amino acids, and

glucose for fuel

With Oxygen!

+Anaerobic Metabolism

Occurs in cytosol of cell Relies solely on glucose for glycolysis Intermediates in glycolysis provide electrons

for electron transport chain in mitochondria (more ATP!)

Events of short duration! <2-3min…But anaerobic and aerobic metabolism often occur simultaneously!

Without oxygen!

+PRACTICE Anaerobic & Aerobic

Julie Galloway, English Channel swimmer. 9hrs 51min

+PRACTICE Anaerobic & Aerobic

Ray Lewis, linebacker for Baltimore Ravens

+PRACTICE Anaerobic & Aerobic

Ryan Lochte, WR 200 medley, 1min 49sec

+PRACTICE Anaerobic & Aerobic

Laird Hamilton, professional surfer

+Factors Influencing the Fuel Mix

During Exercise

1) Intensity of Exercise ↑intensity → ↑CHO use

2) Duration of Activity ↑duration → ↑Fat use

3) State of Training ↑endurance training → ↑Fat

use

Sources of energy for muscle at 3 different intensities of exercise*after about 30 minutes of exercise

+When Fuel Runs Out!http://www.youtube.com/watch?v=LKhkvSRQZYo

+Athletes’ NeedsEnergy

+Athletes’ NeedsEnergy

Female athlete triad: Disordered Eating Amenorrhea Osteoporosis

More common in: Weight-bearing sports (e.g. cross-country) Aesthetic sports (e.g. gymnastics, diving)

+Athletes’ NeedsMacronutrients

Protein 10 to 15% of kcal

Fat 20 to 30%

CHO 55 to 70%

Longer duration training → ↑CHO need Protein 0.8 to 2.0 g/kg body weight

Percentage values assume athletes are meeting energy needs.

Percentages can be very different for athletes attempting weight loss.

+

Recommended Protein Intakes

GroupProtein Intake

(g/kg body weight)Most adults 0.8

Endurance athletes 1.2 to 1.4

Vegetarian endurance athletes 1.3 to 1.5

Strength athletes 1.6 to 1.7

Vegetarian strength athletes 1.7 to 1.8

Dietary Reference Intakes, 2002ACSM/ADA/Dietitians of Canada Position Statement: Nutrition & Athletic Performance, 2001

Protein NeedsExtent of Training & Sources

+Carbohydrate NeedsType & Intensity of Training

6-10g CHO/kg body weight = recommendation (text p.369)

+Athletes’ NeedsMicronutrients Sodium & hyponatremia

Maintains fluid balance in cells Allows for neural firing Problem with water-only fluid replacement in long events

Iron & anemia Exercise increases use of iron

Increased iron-requiring protein synthesis Increased loss through feces, urine, and sweat

Exercise increases need for iron Females and vegetarians at greater risk

+Iron’s Role in Exercisehttp://www.youtube.com/watch?v=eor6EK_JP40&feature=fvwrel

+Questions so far?

+Athletes’ NeedsWaterWater is crucial for:

Blood volume maintaining low heart rate delivering nutrients and oxygen removing wastes

Maintaining low body temperature carrying heat to periphery producing sweat …1.5L/hour!

Why does the body lose so much water during exercise?

1. Working muscles → heat

2. Blood flow carries heat to the skin

3. Evaporation of water from the body surface is the most efficient way to remove heat

**water both transports and removes heat**

Sweat loss ~ 1.5 Liter (~6cups) / Hour

+

Water loss as little as 2% of body weight can impair physical and mental performance. 2% weight loss for 150 lb person = 3 lbs 1.5 liters = ~ 1.5 quarts = 3 lbs

Dehydration Impairs Athletic Performance

+Dehydration & Heat-Related IllnessHeat Cramps

Involuntary muscle spasms caused by heat & electrolyte loss.

Heat Exhaustion Rapid heart rate, low blood pressure, disorientation,

loss of consciousness.

Heat Stroke Can be fatal. Body temp over 105F. Inability to

produce sweat. Extreme confusion, loss of consciousness, death.

+Athletes’ NeedsWaterBefore exercise, drink enough to be fully

hydrated. ~2 cups usually.During exercise, drink enough to prevent

weight loss. 6-12oz every 15-20min. If you’re thirsty, you’re already dehydrated!

After exercise, rehydrate! 16-24oz per pound lost, or 16oz immediately+.

Cooler water is absorbed faster.Water with 6-8%CHO is absorbed faster.

+

Optimizing Performance Nutrition is ImportantBefore, During, & After

Competition

+Optimizing PerformanceBefore

Begin properly hydrated. Maximize glycogen stores.

+

Carbo-Loading

Controversial on best method

~3 days before race, consume 10-12g CHO/kg (140lb ~2800kcal CHO)

Can DOUBLE glycogen stores

Holds 3g water per g glycogen

Can really only be helpful for events >90min

http://www.youtube.com/watch?v=9-e5y-3dyUs

+Optimizing PerformanceBefore

Begin properly hydrated. Maximize glycogen stores.

Carbo Loading (10-12g Cho/kg) to boost glycogen stores. Important for competitions over 90min. Extra benefit of storing 3g water per g glycogen.

Pre-exercise meal ~300kcal high in Cho.Low fat & fiber to minimize GI distress &

bloating.Caution with fructose & diarrhea.

Your gut is trainable!!

+Optimizing PerformanceDuring Prevent excess fluid loss CHO during exercise if lasts >1hr can help maintain

glycogen stores Glucose & fructose combination In sports drink or a gel or snack 30-60g/hr recommended

Sodium during exercise >1hr, especially >3hrs In most sports drinks Improves water and CHO absorption Stimulates thirst

+Optimizing PerformanceAfter Replenish fluid (ASAP), electrolytes, and glycogen lost Provide protein to build and repair muscle tissue High CHO snack within 30min (glycogen window!)

Enhanced repair with some protein 1.0-1.5g/kg CHO for training Regular 55% CHO diet for regular exercisers

+

Ergogenic AidsSubstances, appliances, or procedures that improve athletic performance

+

Ergogenic AidsVitamins & Minerals

Not really an Ergogenic Aid, because typically do not enhance performance at all unless there was a deficiency.

Can cause harmful toxicity!

+Ergogenic AidsBuilding Muscle Protein = Usually adequate in diet of adequate

Calories. Growth hormone = Banned by WADA. Improves

anaerobic exercise capacity but can cause disfigurement and fatal heart dysfunction.

Amino acids = Unhelpful with strength training when adequate complete proteins consumed.

Anabolic steroids = Banned by NCAA and IOC. Hormones that mimic effects of testosterone by increasing muscle size and strength, but cause atrophy of testes, water retention, coronary disease, liver disease, and severe mood swings.

+Ergogenic AidsEnhancing Short, Intense ActivitiesSupplements for improving quick bursts of intense activity: Beta-hydroxy-beta-methylbutyrate (“HMB”) = dubious! Bicarbonate (baking soda) = some results show delayed

fatigue due to its pH stabilization BUT causes cramps & diarrhea …Needs more research!

Creatine = found naturally in muscle (PCr system) Used for <30sec activity BUT body adapts to creatine production <5g/day appears safe but FDA recommends consulting physician

first

+Ergogenic AidsEnhancing Endurance Carnitine = needed to transport FA to mitochondria

But the body makes all we need!

MCT = quickly absorbed FA’s But haven’t shown to help performance!

Caffeine = enhances release of FA’s Preserves glycogen stores & delays fatigue Improves alertness & concentration But can cause GI distress Can improve endurance if take 3-6mg/kg within 1hr (2.5cups of coffee)

EPO = stimulates bone marrow to produce RBCs Banned substances, commonly abused by cyclists Can cause heart attacks & stroke

+Physical Activity Recommendations32% of Americans get NO physical activity in their leisure time!

+Physical Activity Recommendations150min of moderate-intensity or 75min of

vigorous-intensity aerobic zone exercise/wkAerobic zone = 60-85% of HR max

& 2 days/wk of muscle-strengthening exercisesNonconsecutive days

Recovery important for muscle-strengthening exercise & for serious athletes to prevent “overtraining syndrome”

+

Curious?

Advanced Sports Nutrition-By Dan Bernot

Nutrition for Health, Fitness & Sport-By Melvin H. Williams

Australian Institute of Sporthttp://www.ausport.gov.au/ais/nutrition

+

Questions?Please email me!joygallo@hawaii.edu