Chapter 9 - Sports nutrition and energy metabolism Flashcards
respiration
The process of producing energy from fuels using oxygen and producing carbon dioxide and water
VO2 max
The maximum amount of oxygen that can be supplied at any instant in an individual
aerobic
The condition of producing energy through processes that require oxygen
Having sufficient oxygen to do so
Anaerobic
The condition of producing energy through processes that do not require oxygen
Not having sufficient oxygen to produce energy through other processes
How much fat do people store?
5,000 kcals of fat
How much carbohydrate do people store?
2,000 kcal of carbs
Overtraining
A physical state of staleness, tiredness, and even deconditioning caused by too much training and too little recovery
Possibly exacerbated by inadequate nutrition
Aerobic activity
Any type of exercise that increases heart rate qualifies as aerobic
What does strength training do to basal metabolism
Increases basal metabolism more than aerobic
Plyometrics
A strength training method characterized by a rapid stretch of the muscle prior to contraction
Immediate energy system
A system that releases energy stored in creatine phosphate for rapid maximal muscle contraction of very short duration
Anaerboic glycolysis
The process that splits glucose into pyruvate and releases energy to ATP and NADH
Aerobic metabolism
A series of processes that begins with the conversion of pryuvate co acetyl CoA, proceeds to the citric acid cycle, and ends with the electron transport chain; aerobic metabolism produces NADH, H+, FADH2, ATP, CO2 and water, and requires oxygen as the final electron acceptor
ATP
When in use: At all times
Ex. All types
Phosphocreatine (PCr)
When in use: All exercise initially; short bursts of exercise thereafter
Carbohydrate (anaerobic)
When in use: High intensity exercise; especially lasting 30 seconds to 2 minutes
ex. 200 yard sprint
Carbohydrate (aerobic)
When in use: exercise lasting 2 minutes to 3 hours or more; the higher the intensity (6 minute mile), the greater the use
Ex. Basketball, swimming, jogging
Fat (aerobic)
When in use: exercise lasting more than a few minutes; greater amounts are used at lower exercise intensities
Ex. Long-distance running
Ex. Long distance cycling
Ex. 30 minute brisk walk
Protein (aerobic)
When in use: Low amount during all exercise; slightly more in endurance exercise, especially when carb fuel is lacking
Ex. Long-distance running
ATP
Adenosine triphosphate
Common energy source of the body
Inorganic phosphate (Pi)
Simple phosphate groups incorporated into ATP and other molecules and then released in order to transfer energy
Adenosine diphosphate (ADP)
High-energy chemical compound used to transfer energy from nutrients to various life processes
Creatine phosphate (CP)
High-energy chemical compound used to store and release energy in the immediate energy system
Nicotinamide adenine dinucleotide (NAD+)
An intermediary fromed from the vitamin niacin that transfers high-energy electrons released from nutrients as they are metabolized to ATP
Flavin adenine dinucleotide (FAD)
An intermediary, formed from the vitamin riboflavin, that transfers high-energy electrons released from nutrients as they are metabolized to ATP
Niacin
A B-vitamin used as the basis of NAD+
Riboflavin
a B-vitamin used as the basis of FAD
pyruvate (pyruvic acid)
A three-carbon molecule formed from glucose in anaerobic glycolysis
lactate (lactic acid)
A three-carbon molecule formed from pyruvate.
Excess lactate is shuttled to the liver to be converted back to glucose via the Cori cycle
Cori cycle
The process by which accumulated lactate is shuttled to the liver to be converted back to glucose and returned to muscle.
The Cori cycle provides a means to deal with the pyruvate that accumulates during anaerobic glycolysis
Coenzyme A
A compound formed from the B-vitamin pantothenic acid that is combined with pyruvate to create acetyl CoA, which then enters the cirtric acid cycle
pantothenic acid
a B-vitamin used to form coenzyme A, which activates pyruvate for entry into the citric acid cycle
acetyl CoA
formed from pyruvate and coenzyme A
allows pyruvate to enter the citric acid cycle
citric acid cycle
The pathway by which acetyl CoA combines with oxalocetate and through a series of reactions, yields NADH, H+, FADH2, ATP, CO2, and finallly returns to oxalocetate, ready to start the cycle again with another acetyl CoA
krebs cycle
Another name for the citric acid cycle
tCA cycle
another name for the citric acid cycle
oxalocetate
a four-carbon compound that begins and ends the citric acid cycle
Reacts with acetyle CoA to begin the cycle
citric acid
the six-carbon compound that is the product of oxaloacetate and acetyl CoA in the citric acid cycle
Electron transport chain
A series of carrier molecules that transfer the high energy electrons of NADH and FADH along to ATP
Their energy is stored in ATP’s phosphate bonds until the electrons are passed to oxygen so that they combine with hydrogen to form water
three types of carbohydrate
- Glucose that circulates in the blood
- Glycogen in the liver
- Glycogen in muscle
gluconeogenesis
The process by which the amino group is removed from amino acids and they are converted to glucose
break down body proteins to produce glucose
High carbohydrate diets relationship to training
increases the time it takes to reach exhaustion
Low GI contain
starch
High GI contain
sugars
mitochondria
the cell structure where most of the reactions in the aerobic production of energy from fat, carbohydrate, and protein take place
Carnitine
A compound formed from amino acids which shuttles activated fatty acids across the mitochondrial membrane into the mitochondria for beta-oxidation
beta-oxidation
The process by which fatty acids are metabolized, in which they are shortened two carbons at a time and combined with coenzyme A to form acetyl Co for entry into the citric acid cycle
ketone bodies
Compounds that are produced when fat is used for energy balance because of insufficient dietary carbohydrate
Without carbs, oxaloacetate cannot be replenished and acetyl CoA from fat cannot enter the citric acid cycle
The excess acetyl CoA is converted into ketone bodies
Predominant fuel used in low-intensity exercise
Fat
carbon skeletons
The carbon framework of an amino acid
glucogenic
Amino acids which are made into pyruvate and then into glucose through gluconeogenesis
Ketogenic
Amino acids which are made into acetyl CoA for entry into the citric acid cycle, but which cannot be used in gluconeogenesis to make glucose
Female ahthlete triad characteristics
- disordered eating
- amenorrhea
- premature osteoporosis
Amenorrhea
The cessation of normal menstrual periods
Caused by low estrogen levels in the body
leads to osteoporosis
Premature Osteoporosis
Thinning and weakening of bones due to a loss of bone mineral
Percent of body’s energy needs from protein
10 percent
Gluconeogenesis important when?
Fasting
Low carbohydrate diets
prolonged exercise
Exercise increases what?
Protein requirements
Grams of protein for active people
1.2-1.6 grams of protein per kilogram of body weight
Best sources of protein
Beans, low-fat dairy products, and vegetables
*Protein supplements are unnecessary*
100 meter dash (10-15 seconds or intensity)
Energy supplied by the immediate energy system and anaerobic glycolysis
What does the body use ATP for?
to capture the energy from all the macronutrients using a variety of pathways
Egrogenic aids
Substances that enhance physical performance
Examples: caffeine, carnitine, ephedra, creatine, ginseng
What does caffeine do?
Helps release fat stores into the blood stream
Carnitine
The substance that transports fatty acids into the mitochondria for metabolism
Ephedra
Herbal stimulant used for weight loss
side effects: high blood pressure, heart irregularities, and nausea
Creatine
Reult in higher levels of creatine phosphate in the muscle cells
Zinc
Body needs zinc to make new cells
Helps control tissue growth and injury repair
Immune system needs zinc to function at its best
Sources: meat, seafood, dairy products, whole grains, and seeds
Excess zinc?
Inhibits the immune system and reduces absorption of other minerals
Potassium
The major positively charged intracellular ion
Vital for muscle contraction and conduction of nerve impulses
Sources: most fruits and vegetables
Potassium and sweat
Significant amounts of potassium can be lost in sweat so exercise during hot weather can increase potassium needs
Inadequate potassium?
Can impair performance and may cause muscle cramping
Excess potassium
Excreted by the kidneys
high intakes a problem for peope with kidney disease
intracellular
inside cells
Iron
A component of myglobin
required in muscle building
Plays a role in energy metabolism as a component of the electron transport chain
Chormium
Helps insulin bind to its receptor on the cell and is important for synthesis of muscle protein and glycogen
Sources: unprocessed foods and whole grains
Chromium supplements
Increase strength gains from training and may increase lean body mass
May be associated with kidney and chromosome damage
Pyridoxine (Vitamin B6)
Necessary for protein synthesis
Important in muscle repair and growth
Needed for synthesis of non-essential amino acids
Without B6 all amino acids are essential
Deficiency of Pyridoxine (Vitamin B6)
Limits development of lean tissue
High doses of Pyridoxine (Vitamin B6)
May cause neurological damage
Vitamin C
Involved in the synthesis of collagen
Sources: fruits and vegetables
Vitamin C deficiency
Causes poor wound healing and deterioration of connective tissue
Old scares may open, woulds cannot heal, muscles cannot recover
More than 2,000 mg/day of Vitamin C
May cause GI upset
May contribute to oxidative damage to cells
Body can become dependent on high doses from supplements so that if they are discontinued the body develops rebound scurvy
Collagen
The primary protein found in connective tissue
Vitamin C is involved in its synthesis
Scurvy
The disease caused by a deficiency of vitamin C
Antioxidants
Protect muscle and red blood cells from oxidative damage
Neutralize free radicals
Help protect us from heart disease and cancer
Aerobic exercise increases need for antioxidants
Free radical
A highly reactive species of oxygen or other substance capable of damaging cell components and contributing to cancer and heart disease
Vitamin C also acts as what?
An antioxidant
water-soluble vitamin
Vitamin E
Antioxidant
Fat-soluble vitamin
Significant antioxidant
Sources: seeds, nuts, seed oils, and vegetables
Best source: wheat germ
Vitamin E deficiency
Can cause hemolysis
Excessive intake of vitamin E
May interfere with absorption of vitamin K
Hemlolysis
Red blood cells break down when they are not protected against oxidative damage
Caused by a deficiency of Vitamin E
Selenium
Antioxidant
component of the glutathione peroxidases
Sources: meats, seafood, and whole grains
High doses of selenium
Selenium toxicity - causes loss of hair and nails
glutathione peroxidase
A group of anti-oxidant enzymes
Carotenoids
Best-known = beta carotene
antioxidant activity
sources: fruits and vegetables (colorful ones because carotenoids are strong pigments)
High levels of carotenoids
Contribute to oxidative damage
Impossible from vegetables and fruits, yet a real concern with supplements
Beta-carotene
Best-known carotenoid
Body uses it to make vitamin A
Hemoglobin
Iron-containing portein found in red blood cells
binds with oxygen in the lungs and releases it in the muscles
Transports carbon dioxide back from muscles to the lungs
Erythropoiesis
synthesis of red blood cells
erythrocytes
red blood cells
Folate
important for cell division to produce new red blood cells
necessary for the formation of the new DNA
Sources: dark leafy greens, beans, and orange juice
Insufficient folate
cell division cannot occur and cells continue to grow big without dividing
causes macrocytic anemia
High intake of folate
Can mask symptoms of viamin B-12 deficiency
Macrocytic
A type of anemia in which red blood cells are too big, caused by folic acid deficiency (folate)
Vitamin B-12
Regenerates folate after it has been used by the cell
Sources: only animal products: meats, fish, poultry, and dairy products
Vitamin B-12 deficiency
produces a secondary deficiency of folate
vegetarians at risk for vitamin B-12 deficiency
High intake of vitamin B-12
no negative consequences
Vitamin B-6
Helps to synthesize hemoglobin
Vitamin B-6 deficiency
Results in inadequate amounts of hemoglobin for red blood cell production
Micocytic anemia
A type of anemia in which red blood cells are too small
Caused by iron deficiency
Athletes and iron
Blood volume increases in athletes so need more iron
Readily absorbed forms of iron
Meat
Fish
Poultry
Less readily absorbed forms of iron
Dark leafy greens
Beans
Dried fruits
Fortified cereals
other plant foods
Vitamin C deficiency
Can contribute to the development of iron deficiency
Defiency of B-vitamins
Exhaustion
Weakness
Fatigue
Lethargy
Loss of coordination
Niacin
Used to make nicotinamide adenine dinucleotide (NAD+)
Mostly found in high-protein foods
High doses of niacin
severe flushing
Liver damage
Riboflavin
made into flavin adenine dinucleotide (FAD)
Sources: milk and dark leafy greens
Thiamin
used to make the coenzyme thiamin pyrophosphate (TPP)
important for nerve and muscle metabolism
Sources: foods high in protein and whole grains
thiamin definition
a B-vitamin used as the basis of TPP
thiamin pyrophosphate (TPP)
a coenzyme which helps convert pyruvate to acetyl CoA and participates in the citric acid cycle
Adequate intakes of calcium
needed to achieve high bone mineral density
Sources of calcium
Dairy products and dark leafy greens
Vitamin D
necessary for absorption of calcium from the gut
Source: fluid milk
Can come from sun
Vitamin D deficiency
creates a calcium deficiency
malformation of bone - rickets
Vitamin K
Helps maintain the protein matrix of bone
Sources: green leafy and cruciferous vegetables
Vitamin K defiency
contribute to bone fractures
Excessive intake of Vitamin A
may weaken bone
caused by overuse of fortified foods and supplements
Body’s main method of losing heat?
sweating
Exercise in hot weather
lose as much as one to three liters of sweat per hour
Dehydration
2-3% of body weight as water
Cause death
heat stroke
loss of electrolytes
acute kidney failure
poor decisions
electrolyte
an atom which carries an electrical charge because of loss or gain of elecrons and is found dissolved in fluid
hyponatremia
The condition of having a low concentration of sodium in the blood
Over drinking water
Sodium and potassium
most important electrolytes lost in sweat
Hypokalemia
The condition of having a low concentration of potassium in the blood
Isotonic
A fluid with solute concentrations equal to those found in body fluids
Sports drinks
Hypertonic
A fluid with solute concentrations greater than those found in bodily fluids
soft drinks
