Module 9 Flashcards
Fitness
• Definition: – Ability to perform routine physical activity without undue fatigue • Overload Principle – Body will adapt to stresses placed on it • Parameters – Cardiorespiratory Endurance – Muscle Strength and Endurance – Flexibility – Healthy Body Composition
Cardiorespiratory Endurance
• Determines how long one can continue a task with an
elevated heart rate
– Requires muscle strength
– Involves
• Cardiovascular system
• Respiratory system
• Endurance is increased by aerobic exercise (any exercise that
increases heart rate and requires oxygen in metabolism)
– Increases stroke volume decreases resting heart rate
– More fit people have slower resting heart rates
Cardiorespiratory Endurance
Increases maximal oxygen consumption • Depends on – Body’s ability to deliver oxygen to cells – Cells’ ability to use oxygen to produce energy • Aerobic capacity, VO2 max, is the body’s ability to generate ATP by aerobic metabolism during exercise • The greater the VO2 max the more intense an activity the person can engage in before lack of O2 affects performance
Health Benefits of Exercise
• Maintenance of a healthy body weight – Increase lean tissue and limit body fat – More lean tissue keeps energy needs high • Reduces risk of cardiovascular disease – Strengthens heart – Lowers blood pressure – Increases HDL cholesterol • Reduces risk of Type II Diabetes – Improves insulin sensitivity
Health Benefits of Exercise (Cont.)
• Reduces risk of Osteoporosis and Joint Disorders
– Weight-bearing exercise can increase bone mass and
reduce bone loss
– Exercise can benefit those with arthritis by increasing
strength and flexibility
• Reduces risk of some cancers
– Breast and colon
• Mood Elevation
– Release of endorphins
ATP (energy source)
– The immediate source of energy for all body functions
– Small amounts stored in muscle
Creatine Phosphate (Energy Source)
– A compound found in muscle that can be broken down
to generate ATP
ATP is used for energy during exercise in…
– In resting muscle, there is enough ATP to
sustain an intense activity for a few seconds
– Creatine Phosphate is sort of a “back-up”
supply of energy to make ATP in muscle
• Enough to fuel 10-15 seconds of exercise
ATP needs to be replenished from:
– Fat, carbohydrate, and protein metabolism
– Through electron transport chain
Availability of Oxygen
– If oxygen is available, fat, carbohydrates, and protein can all be burned for energy •Aerobic metabolism – If oxygen is unavailable, then only carbohydrates can be used for energy •i.e. Anaerobic metabolism
Energy usage for slow exercise:
• If you are exercising slowly enough that you have
oxygen to run electron transport chain:
– You are using primarily fatty acids for energy
Energy Usage for Intense exercise
• If you are exercising so intensely that the body or
specific muscles cannot get enough oxygen to run
electron transport chain:
– You are using glucose through glycolysis
– Producing lactic acid as a by-product
Fat as an Energy Source
• Fatty acids must be transported into mitochondria to be
burned
– Requires the molecule carnitine
– Carnitine supplements marketed to athletes
Carnitine
• Carnitine is made by the body from amino acids
– Does not need to be eaten
– No evidence that healthy people…
• Burn more fat with carnitine supplements
• Have better endurance with supplements
Effect of Training
• Training results in physiological changes that
allow you to better burn fat for energy
– Can go longer without switching to glycogen
(limited supply)
•More blood delivered with each beat
•Increased capillary vessels to muscles
•Increased number of muscle cell
mitochondria
• Increased ability to store muscle glycogen
Energy needs are affected by
– BMR, TEF and PA
Ideal Energy Source Composition:
• Carbohydrate – 55-60% of kcal to replace muscle and liver glycogen stores used by exercise • Fat – Same as recommended for general population, < 30% of kcal from fat • Protein –10-20% of energy needs •Can get proteins from food
Iron
• Regular intense exercise can increase
iron needs 30-70%
Calcium (Ca)
• Female Athlete Triad
– Interrelated disorders that are common in female
athletes who strive to lose body weight and body fat to
promote performance
• Exercise combined with disordered eating can cause low
estrogen levels
– Can cause menses to stop
• Low estrogen interferes with Calcium status
– Results in a reduction in bone mass and bone mineral
density
• Combined with low Calcium intake
– Premature bone loss, failure to reach peak bone mass,
and increased risk of fractures
Water is needed to
– Regulate body temperature
– Transport oxygen and nutrients to the muscles
– Transport waste products away from muscles
Thermal distress
• Caused when lost water is not replaced – Dehydration • Blood volume is decreased – Heat cramps • Caused by imbalance of water & electrolytes – Heat exhaustion • Too little blood to both cool body & deliver oxygen to active muscles – Heat stroke • Most serious, when temperature regulatory center of the brain fails
Glycogen Loading
• Involves depleting glycogen stores by exercising strenuously and then replenishing glycogen by consuming a high-CHO diet for a few days before competition – Can increase glycogen stores 20 -40% – 3 g water associated with each g of glycogen stored – Is beneficial for endurance athletes • Not for exercise of short duration
B-vitamins
• In general, B vitamins serve as coenzymes (Module 2)
– Act as carriers of electrons or atoms in metabolic
reactions
– Primarily in energy metabolism
– Also important in amino acid metabolism
Ergogenic
Something that increases physical performance.
Coenzymes
Vitamins
Cofactors
Minerals
Cofactors for Enzymes
• Essential in diet
• Do not provide energy, but instead:
– Aid in chemical reactions to produce energy from
macronutrients
– Facilitate other essential chemical reactions
– Are required for the proper functioning of many
enzymes (which are proteins)
•Cofactors themselves are not proteins
Niacin
Important in energy production from energy-containing nutrients.
• Active coenzymes:
– NAD or NADH (nicotinamide adenine dinucleotide)
– NADP or NADPH (nicotinamide adenine dinucleotide
phosphate)
Riboflavin
A vitamin that is:
• Made into 2 active coenzymes:
– FAD or FADH2 (flavin adenine dinucleotide)
• Functions in the citric acid cycle and the breakdown of
fatty acids
• Like NADH it is “cashed in” for ATP (2) in the electron
transport chain
– FMN (flavin mononucleotide)
• Serves as electron carrier in electron transport chain
Thiamin
• Important in energy-releasing reactions
• Active coenzyme: thiamin pyrophosphate (TPP)
– In reactions where CO2 is lost from larger molecules
• Production of Acetyl CoA from Pyruvate
• TCA cycle
Biotin
• Needed for some reactions in gluconeogenesis
• Also important in the metabolism of fatty acids
and amino acids
• Found in liver, egg yolks, yogurt, and nuts
Pantothenic Acid
• Makes: coenzyme A (CoA) – Is part of acetyl-CoA •Acetyl CoA is produced during the breakdown of –CHO –Fatty acids –Amino acids
B6 (pyridoxine)
• Active coenzyme: PLP (pyridoxal phosphate) – Needed by > 100 enzymes involved in metabolism of CHO, fat, & protein • to make non-essential amino acids • to degrade excess amino acids • to convert amino acids to glucose for energy – The more protein you eat, the higher your requirement for B6
Folate (folic acid)
• Metabolism of some amino acids • Synthesis of DNA – Makes it particularly important in production of red blood cells • Deficiency causes anemia
B12 (Cobalamin)
• 2 active coenzymes
– 1 necessary for the conversion of fatty acids to energy
– 1 necessary in metabolism of the AA methionine
• Also critical in regenerating active folate
– A B12 deficiency can cause a folate deficiency
Vit C, Vit E and Beta Carotene
• Antioxidant supplements which are promoted in athletes
because exercise
– Increase electron transport
• higher production of free radicals
• Supplements have been shown to prevent
oxidative damage but not enhance performance
Ergogenic Aids
• Some Mineral Supplements promoted – Chromium – Vanadium – Selenium – Zinc – Iron • Summary – No known benefits – Potential toxicity
Chromium Picolinate
– Chromium is needed for insulin action •Insulin promotes protein synthesis • Human studies – No beneficial effect on •Muscle strength •Body composition •Weight loss •Other aspects of health
Creatine
• Creatine is synthesized by our body and is found in
the diet in meat and milk
– Supplements have been found to increase muscle
creatine
– Provides muscles with more quick energy for
activity, delays fatigue
– Allows creatine phosphate to be regenerated
more quickly after exercise
– Enhances strength, performance and recovery
– Impairs accumulation of lactic acid
Caffeine
• Caffeine has been shown to enhance performance
during prolonged moderate-intensity endurance
exercise and short-term intense exercise
• May release fatty acids as a fuel source
– Glycogen is spared
– Delaying the onset of fatigue
• In some athletes caffeine may impair performance
by increasing water loss in the urine
– Or causing gastrointestinal upset
Ginseng
– Promoted to increase endurance
– In certain amounts, it has been shown to increase
muscle strength and aerobic capacity
• Benefits may be greater for older subjects
– Generally considered to be safe
• May increase side effects of other stimulants like
caffeine
Ephedrine/ephedra
– Stimulant that mimics the effect of epinephrine
(adrenaline)
• Lower doses, when combined with caffeine, have been
shown to
– Increase time to exhaustion in exercise
– Promote a reduction of body fat during weight loss
– Side effects include
• nervousness, headache, hypertension, cardiac
arrhythmias and even death
