Sport and Exercise Nutrition Exam 3

Carbohydrate and fat are always oxidized together in varying proportions. Name 3 factors that determine this proportion during exercise:

-exercise intensity -exercise duration -level of aerobic fitness - diet -CHO intake before or during exercise

Name 2 things that a sport drink should accomplish:

1. hydrate effectively 2. replenish electrolytes 3. provide energy for working muscles to enhance performance and speed recovery

During moderate intensity exercise which of the following 4 things occur to increase fat oxidation?

1. lipolysis is increased three-fold 2. blood flow to adipose tissue is doubled 3. re-esterification is cut in half 4. skeletal blood flow increases dramatically, delivering increased amounts of fatty acid for energy conversion

How does dehydration specifically affect performance?

1. reduction in blood volume leading to a increased cardiovascular strain 2. decreased heat dissipation due to decreased skin blood flow and sweat rate 3. decreased heart rate at any given intensity 4. increased rate of muscle glycogen use

according to the ACSM position stand on exercise/fluid replacement, what quantity of sodium should be added to a rehydration beverage?

500-700mg/L

what is the minimum amount of fluid recommended by most of the scientific organizations regarding consumption 2-3 hours prior to exercise/competition?

500ml or 17oz

if freddy evaporates 2 liters of sweat from his skin, approximately how many Kcals worth of heat has he removed from his core?

573 per liter so =1146 kcal's

Fat oxidation is decreased dramatically at what intensity of exercise?

75% VO2 max

what percentage of body weight loss to sweating results in a dehydration level that can impair exercise performance?

>2%

The complete oxidation of fatty acids in the mitochondria depends on:

beta oxidation enzyme activity, concentration of TCA cycle intermediates and TCA enzyme activity, and presence of oxygen

Which of the following has the least effect on fat oxidation?

carnitine supplementation

air flowing over the skin is and example of heat loss from the body via which method

convection

TRUE/FALSE: a good rule of thumb is to drink 20-24 oz fluid every 15 minutes or so during activity

false

TRUE/FALSE: someone with a 6 and urine that is yellowish in color would be considered well hydrated

false

TRUE/FALSE: women, in general, demonstrate higher sweat rates than men but are less likely to develop exercise-associated symptomatic hyponatremia

false

INCREASE or DECREASE: the effect that adding glucose or sodium has on fluid absorption across the membrane of the small intestine

increase

An increase in core temperature will result in an immediate increase in blood flow to the skin and what other "cooling related" action?

initiation of sweating

this mineral is involved in hundreds of physiologic reactions such as glycolysis, fat metabolism, ATP hydrolysis, membrane stability, and supplementation helps prevent muscle spasms and cramps. Female athletes and weight control athletes are often deficient

magnesium

what are the potential reasons that dehydration will adversely affect athletic performance?

reduction in blood volume, decreased skin blood flow, decreased sweat rate, and increased rate of muscle glycogen use

the capacity of the aerobically trained muscle to use fatty acids as a fuel results in

reduction in lactic acid formation, sparing of muscle glycogen, and sparing of blood glucose

Hormone sensitive lipase (HSL) mediates lipolysis. The conversion of HSL from its inactive form to it active form mainly depends on (is stimulated by):

the sympathetic nervous system and circulating epinephrine released from the adrenal medulla

Role of sodium in a sports drink

to maintain thirst, to prevent hyponatremia, to increase palatability, and to increase retention of fluid

TRUE/FALSE: a body temperature of 36 to 38°C is the normal range at rest, and it may rise to 38 to 40°C during exercise

true

TRUE/FALSE: if energy intake matches the energy requirement and an athlete consumes a reasonably balanced diet, he or she will get all the vitamins necessary from food without any need for supplementation.

true

TRUE/FALSE: magnesium deficiency in both humans and animals is associated with neuromuscular abnormalities, including muscle weakness, cramps, and structural damage of muscle fibers and organelles.

true

TRUE/FALSE: performance is not improved by taking vitamin and mineral supplementation unless a deficiency exists

true

TRUE/FALSE: the rate of heat transfer away from the body core is the product of the skin blood flow and the temperature difference between the core and the skin

true

TRUE/FALSE: the thirst signal is the result of being slightly dehydrated

true

Name one of the easiest ways for an athlete to determine fluid loss or hydration status

urine color chart and pre & post exercise weight difference

anemia is likely to be caused by a deficiency of

vitamin B12 (cyanocobalamin), B9 (folic acid), E (tocopherol), iron, vitamin C (ascorbic acid)

deficient intake of this mineral leads to decreased power/strength by decreasing ability to use glucose anaerobically and reduced endurance performance by decreasing the ability to eliminate CO2 via carbonic anhydrase

zinc

this vitamin functions to help in the production of red blood cells (erythrocytes) and supports neurologic function

B12 (cobalamin)

this vitamin is required for oxidative energy production as flavin adenine dinucleotide (fad)

B2 (riboflavin)

this vitamin is required for oxidative energy production as nicotinamide adenine dinucleotide (nad)

B3 (niacin)

this vitamin plays a role in transport of fatty acids into mitochondria, involved in synthesis of epinephrine and norepinephrine, potent anti-oxidant, and supports recovery through enhanced immune function, antioxidant action, and collagen repair

C (ascorbic acid)

TRUE/FALSE: insulin stimulates lipolysis in adipose tissue

False

As exercise intensity increases (up to about 75% VO2max), fatty acid oxidation ____ from low to moderate exercise.

Increases

this mineral is required for delivery of oxygen and utilization of oxygen to produce energy and is associated with hemoglobin, myoglobin, cytochromes, and specific enzymes

Iron

TRUE/FALSE: intramuscular triacylglycerols (IMTGs) are a key energy source for aerobic exercise and training increases the concentration of IMTGs near mitochondria

TRUE

TRUE/FALSE: exercising for prolonged periods in the heat without fluid intake also increases risk of cramps and heat illness.

True

TRUE/FALSE: fish oil (long chain omega 3 fatty acid) have been shown to improve cell membrane integrity and function

True

TRUE/FALSE: intramuscular triaclyglycerol stores are higher in trained people than they are in their untrained counterparts and in Type 1 muscle fibers more so than Type 2

True

TRUE/FALSE: the hypothalamus is primarily responsible for integrating the sensory inputs from the skin and core receptors during heat gain

True

List some micronutrients that have an antioxidant function:

Vit A, C, E, iron, zinc

A deficiency of the micronutrient ___ is associated with weakening of the bones

Vitamin D

name two sources of fat for energy production in the body:

adipose tissue and muscle triglycerides

The transport fatty acids in the blood is the result of ___, from the blood stream into the cell through the sarcolemma due to ____, through the sarcoplasm to the mitochondria via ___ and lastly is shuttled into mitochondria by ____.

albumin, FAT/CD36, FABPpm, carnitine

which of the following contributes to "environmental" heat stress?

ambient temperature relative humidity wind velocity (convective flow) solar radiation

At low and moderate intensity exercise, fatty acids are readily available due to:

an increase in lipolysis and suppression of fatty acid re-esterification