Sports Nutrition (EXAM 3)

thermoregulation and aerobic

• water serves many purposes in the body, our focus

  • ___________

    • Avoiding heat-related disorders

  • _______ exercise performance

    • maintaining cardiac output

reduces

when we sweat, the water comes from our plasma, thus sweating _______ plasma volume

Hypovolemia

less than the normal extracellular fluid (blood) volume

greater than

hydration guidelines suggest preventing _______ _____ 2% body mass deficit from water loss

Thermoregulation

• lower plasma volume = less blood that can be diverted to the skin

  • increased body temperature → heat-related illness

cardiac output

• lower plasma volume = less blood returning to heart (venous return) = lower stroke volume = lower cardiac output

  • this (L*min-1) = SV x HR

    • stroke volume = how much blood heart pumps out

    • heart rate = beats per minute

      • want both to be high

• how much blood your heart pumps out per minute

65%

the whole body is approximately how much water (H20)?

extracellular fluid and intracellular fluid

what are the two major fluid compartments in the body?

extracellular fluid

• two types of this:

  • plasma (intravascular) (less)

  • interstitial fluid (intercellular) (more)

intracellular fluid

• fluid within the cells

• holds 2/3 of total body water

water

Cell membranes and blood vessels, specially the capillaries, are permeable to _______. It can move between compartments under certain circumstances (Osmotic pressure gradient)

Osmolality

• number of dissolved particles, known as solutes, in a solution

  • this of the ECF and ICF is normally around 275-295 mOsm*kg-1

• is primarily determined by electrolytes

  • ECF: Na+

  • ICF: K+

• is determined by the number of particles not the size of the particles

osmotic pressure

water moves from areas of low osmolality to areas of high osmolality

Isotonic

compartments have equal osmolality

hypertonic

• high osmolality relative to adjacent compartment

• more dissolved solute

hypotonic

• low osmolality relative to adjacent compartment

• less dissolved solute

hypotonic to hypertonic

water moves from _________ side to ________ side to try to create isotonic

lower to higher

water moves from an area of _______ solute concentration to an area of ________ solute concentration

sodium

key electrolyte outside the cell

potassium

key electrolyte inside the cell

shrinks

ECF is hypertonic to ICF → cell ______

swells

ECF is hypotonic to ICF → cell _____

outside

sweat comes from _______ the cell

sweat

______ comes from the ECF and primarily contains water and NA+, but we lose more water relative to Na+

• this increases plasma osmolality

lower

When rehydration is the main goal the osmolality of a sports drink should be _______ than that of the blood. This will maximize the rate of rehydrate.

dehydrating

In this scenario, the CES is too concentrated (hypertonic relative to the plasma where you are trying to get water to). The result is that water can move the wrong way, into the small intestine instead of out of it, temporarily ___________ an individual.

osmoreceptors

the hypothalamus, in the brain, has specialized cells called ____________ that monitor osmolality

baroreceptors

blood vessels and the heart contain ___________ that monitor blood pressure

pituitary gland

As plasma osmolality increases, and blood volume/pressure decreases, due to excessive sweating/dehydration, the hypothalamus signals the _______ ______ to release antidiuretic hormone (ADH)

antidiuretic hormone (ADH)

• stimulates the kidneys to reabsorb water, thus lowering the osmolality of the plasma and increasing blood volume/pressure

• is released by the pituitary gland

aldosterone

• a hormone secreted by the adrenal cortex, regulates plasma Na+

• low blood Na+ stimulates the release of this

  • increases sodium reabsorption in the kidney

  • water is naturally reabsorbed with the sodium

ADH and aldosterone

together, ____ and _________ attempt to counteract the effects of fluid and sodium loss from excessive from sweating

sweat

• ______ rates vary by person and environmental condition

  • Normal range: 0.5-2.0 L*hr-1

    • around 700-1400 mg of Na+ per L

• Monitor body weight fluctuations

• Monitor urine color

• Commercially available testing services

water, CHO, and electrolytes

• ______, ______, and __________ are the main ingredients in sports drinks

  • aka, carbohydrate-electrolyte solution

• the primary goals of a sports drink

  • Hydration (water replacement)

  • Electrolyte replacement (Na+)

  • CHO intake

lower

sports drinks with an osmolality ________ than or equal to the blood (hypotonic or isotonic) move rapidly from the GI tract into the bloodstream

high

conversely, drinks with _____ osmolality (hypertonic) pull water out of the bloodstream and into the gut to dilute the heavy concentration of solutes, which delays hydration and may cause GI distress

sports drink

• drinks with a 6-8% concentration match the osmolality of the blood (isotonic)

  • translates to 6 to 8 grams of carbohydrates per 100 milliliters of fluid

• CHO type; multiple sources of ideal

  • glucose and fructose

    • glucose/dextrose, sucrose, and maltodextrin are most common

• sodium (different for each person)

hyponatremia

• is a condition of below normal levels of sodium in the blood (<135 mmol*L-1)

• due to overconsumption of water

• most commonly occurs during long endurance events but may occur in other sports

hyponatremia

• minor signs and symptoms (Na+ <130 mmol*L-1)

  • Bloating

  • Puffiness of hands and feet

  • Nausea

  • Vomiting

  • Headache

• Severe (Na+ <120 mmol*L-1)

  • Seizures

  • Coma

  • Respiratory arrest

  • Brain damage

  • Death

hyponatremia

to avoid _________ during training it is best to

• drink when you are thirsty

• drink a sports drink that has Na+ in it

fat-soluble vitamins

• stored in liver and adipose cells

• transport in blood requires carrier

• storage protects against deficiencies

• vitamines D, A, K, E

• dissolve in fat

water-soluble vitamins

• circulate easily in blood

• excess is excreted

• no designated storage site

• eight B vitamins and vitamin C

• dissolve in water

inadequate

many adults likely consume _________ amounts of several vitamins particularly vitamin A, D, E, and C

vitamin deficiency

• progress from mild to moderate (subclinical) to severe (clinical)

• the progression through mild and moderate-deficiency stages is difficult to monitor and recognize

dietary reference intake (DRI)

the vitamin demands for most athletes can be met by consuming the amounts recommended by the _______ _________ _______; there is also a built-in margin of safety

vitamin A

• Names:

  • In animal sources: retinol, retinal, and retinoic acid

  • In plant sources: carotenoids, including beta-carotene

• Major physiological functions:

  • overall health of cells and membranes resulting in proper vision, reproduction, bone and tooth development, immune system function; carotenoids are antioxidants; regulates gene expression in cell nuclei involving enzymes, growth factors, and cell death

• food sources:

  • animal: liver, fish oil, milk and milk products (fortified)

  • plant: dark-green leafy vegetables; orange fruits and vegetables (for example: carrots, cantaloupe, tomatoes)

vitamin D

• Names;

  • calciferol, cholecalciferol

• Major physiological functions:

  • regulates bone mineralization, cardiac and skeletal muscle, and growth of normal and cancerous cells

• Food sources:

  • fish oil; some fish such as salmon, macherel, tuna, and shrimp; milk and yogurt (fortified); margarine (fortified); egg yolk

Vitamin E

• Names:

  • tocopherol (for example: alpha-tocopherol, beta-tocopherol)

• major physiological functions:

  • antioxidant; proper red blood cell formation; affects cell signaling

• Food sources:

  • oils, particularly sunflower and safflower oils; soybeans; almonds, hazelnuts, and other nuts, including peanuts; sunflower seeds; wheat germ

vitamin K

• names:

  • phylloquinone

• major physiological functions:

  • normal blood clotting; role in bone mineralization

• food sources:

  • green leafy vegetables; oils; margarine

vitamin B1

• Names:

  • Thiamin

• Major physiological functions:

  • release of energy from carbohydrates, proteins, and fats via thiamin-containing enzymes; normal nervous system function

• food sources:

  • whole grain breads and cereals; bread and cereals made from processed grains or flour (fortified); dried beans, meats (particularly pork)

vitamin B2

• names:

  • riboflavin

• major physiological functions:

  • release of energy from carbohydrates, proteins, and fats via riboflavin-containing enzymes; normal skin development

• food sources:

  • milk; leafy green vegetables; whole grain breads and cereals

vitamin B3

• names:

  • niacin, nicotinic acid, nicotinamide

• major physiological functions:

  • release of energy from carbohydrates, proteins, and fats via niacin-containing enzymes

• food sources:

  • meat, fish, poultry, and eggs; milk; nuts; whole grain breads and cereals; bread and cereals made from processed grains or flour (fortified)

vitamin B6

• names:

  • pyridoxine

• major physiological functions:

  • release of energy stored in muscle glycogen; role in gluconeogenic processes (for example: manufacture of glucose from protein fragments); red blood cell formation; influences gene expression

• food sources:

  • whole grain breads and cereals; dried beans; leafy green vegetables; bananas; meat, fish, and poultry

vitamin B12

• Names:

  • cobalamin, cyanocobalamin

• Major physiological functions:

  • synthesis of new cells; nervous system; red blood cell formation; activation of folate

• Food source;

  • animal foods only; specially formulated yeast or other fortified foods

folate

• Names:

  • folate (when found naturally in food) or folic acid (when added to fortified foods or in supplements)

• Major physiological functions:

  • synthesis of new cells; red blood cell formation; influences gene expression

• food sources:

  • leafy green vegetables; whole grain breads and cereals; dried beans; bread and cereals made from processed grains or flour (fortified); orange juice

pantothenic acid

• name:

  • no other name

• major physiological functions:

  • release of energy from carbohydrates, proteins, and fats via acetyl CoA; can enhance gene expression and promote transcription

• food sources:

  • widely distributed in food

biotin

• names:

  • no other names

• major physiological functions;

  • release of energy from carbohydrates, proteins, and fats; involved in the transcription of some genes

• food sources:

  • widely distributed in food

vitamin C

• names:

  • ascorbic acid

• major physiological functions:

  • collagen synthesis; antioxidant; immune function; aids absorption of iron

• food sources:

  • oranges, grapefruit, other citrus fruits, strawberries, cabbage, broccoli, peppers, tomatoes

coenzymes

• many vitamins are involved with enzymatic activity, particularly as part of a _________ (also called cofactors)

  • are usually involved in speeding up a reaction

B vitamins and C

• all ___ _________ act as coenzymes

  • many of the coenzymes are involved in energy metabolism

• vitamin ___ also acts as a coenzyme but primarily in reactions that involve the synthesis of collagen

not

enzymes function at maximum velocity when saturated with a substrate; more coezyme will ____ increase the rate of the enzymatic reaction

clinical deficiency

however, a ________ ________ of a vitamin (ex: thiamin) will result in fatigue due to a lack of coenzyme synthesis; these deficiencies are rare

energy metabolism

vitamins involved in _______ _________

• B-complex vitamins

  • thiamin (B1)

  • Riboflavin (B2)

  • Niacin (B3)

  • Vitamin B6

  • Pantothenic acid

  • Biotin

free radicals

• highly reactive, unstable molecules created when an atom or molecule gains or loses an electron

• bad

• can be produced in the body during normal cellular metabolic processes or taken into the body from the environment

• excessive production of this can damage cell membranes, DNA, lipids, and proteins

  • increases risk of diabetes, cancer, CVD, Alzheimer’s, and premature aging

free radicals

• sources of ______ ________

  • aerobic cellular reactions (increased in athletes)

  • air pollution

  • pesticides

  • radiation exposure

  • cigarette smoke

  • ozone exposure

  • fried foods and alcohol

antioxidants

• neutralize free radicals by donating electrons to free radicals

  • minerals

    • copper, zinc, selenium, manganese, and iron

  • vitamins

    • vitamin A as beta-carotene, C, and E (ACE)

  • additional molecules

    • glutathione, coenzyme Q10, lipoic acid, flavonoids, phenols, polyphenols, phytoestrogens

      • most of these are in plant-based foods

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