Benefit to physical Activity and Acute Response to Aerobic Activity Flashcards
Study of Exercise science
Provides understanding of how the body responds to acute and chronic demands placed on it by increased energy demand placed on it from exercise.
Physical activity
any bodily movement comes about from contraction of skeletal muscle and increase energy expenditure. (exercise and everyday activities)
Exercise
Structured form of physical activity that has specific purpose.
4 components of physical fitness
- muscular fitness through muscular strength and endurance. muscular strength
- Cardiovascular or cardiorespiratory endurance (aerobic) maximal capacity of heart, blood vessels, and lungs to deliver oxygen and nutrients to working muscles so energy can be produced.
- Flexibility ability to move joints through their normal range of motion. prevent injuries.
- Body Composition- makeup of body in relation to proportion of lean body mass and body fat.
lean body mass
muscles, bones, nervous tissue, skin, blood organs. high metabolic rate and are positive influence to physical performance.
essential fat
How much for men and women?
amount of fat necessary for maintenance of life and reproduction. men 2-5% body fat and women 10-13% body fat.
At rest body is under control of which nervous system?
Parasympathetic
With onset of exercise what happens to nervous systems?
Parasympathetic system is inhibited. Sympathetic takes over. stimulated cardiovascular system and adrenal glands release catecholamines: Epinephrine and norepinephrine.
oxygen consumption during aerobic exercise (table)
when start exercise is immediate oxygen deficit (2-4 minutes), until meet steady state. then when cessation of exercise have Excess Post Exercise Oxygen Consumption (EPOC)
if exercise intensity too high and you cannot reach steady state?
have to supplement ATP production via anaerobic metabolism. lactate accumulates and exercise can only be done for a couple of minutes. Start to get buildup of CO2 so you hyperventilate to blow off CO2.
First ventilatory threshold
first time lactate begins to accumulate in the blood and is caused by need to blow off excess CO2.
Second ventilatory threshold
lactate is rapidly increasing with intensity. usually is point where blowing off Co2 not adequate to buffer increase in acidity.
What percent are athletes in Vt1 and VT2?
VT1- 70-80%, between VT1 and VT2- Less 10%, above VT2- 10-20%
Responses to BP during exercise (systolic and diastolic)
Systolic BP- increases in linear fashion throughout exercise.
Diastolic- stays the same or decreases slightly during exercise.
During Exercise total energy expenditure increase by how many times?
15 to 25 times
Cardiac output is product of which 2 things
Heart rate and Stroke volume
Sinoatrial Node (SA Node)
Posterior wall of the right atrium. Serves as the Pacemaker for the heart. spontaneously depolarize and repolarize to provide innate stimulus for heart contractions.
Atrioventricular Node (AV Node)
located on floor of right atrium. facilitate ventricular contraction. Atria contract first, then the ventricles
Vagus nerve
Parasympathetic fibers, that reach Sa and AV nodes, release acetlycholine to decrease activity os SA and AV nodes to reduce heart rate. At rest heart is under influence of Vagus nerves (Parasympathetic Tone). Decrease in parasympathetic tone increases heart rate, and an increase in parasypmathetic tone decrases HR.
Frank Starling Mechanism
The Stroke Volume of heart increases in response to an increase in volume of blood in ventricles before contraction.
Vasoconstriction in exercise
sympathetic stimulation causes decrease in blood for non exercising muscles except heart.
Vasodilation
prepares the muscle for action by allowing more blood into exercising tissues.
blood flow distribution at rest and during exercise for organs
Muscles- Rest: 15-20% and Max Energy: 84% Liver- Rest: 27% and Max energy: 2% Heart- Rest: 4% and Max Energy: 4% Skin- Rest: 6% and Max Energy: 2% Brain- Rest: 14% and Max Energy: 4% Kidneys- Rest: 22% and Max Energy: 1%
Summary:
Blood Flow increases to muscles
Stays same in Heart
Decreases in all other organs
Transient Hypertrphy
When fluid accumulates during resistance training. Appear Pumped up from exercise. Does down after a few hours.
Minute Ventilation
volume of air breathed per minute. During higher intensity exercise after VT2 minute ventilation increases disproportionally to increase oxygen consumption.
Tidal volume
volume of air inhaled and exhaled per breath.
Catecholamines
Epinephrine and Norepinephrine, are hormones of sympathetic nervous system. Located in adrenal gland atop each kidney.
Epinephrine responses (slight norepinephrine response)
increases cardiac contraction
vasoconstriction in non exercising muscles
vasodilation of heart
Epinephrine only dilates respiratory passage to aid in moving air
Influences blood glucose levels (stimulates carbs and fat to make them available as energy for muscles)
epinephrine stimulates CNS
Insulin
hormone released by pancreas. Directly involved in uptake of glucose into tissue. Exerts a hypoglycemic effect by reducing blood glucose levels and promotes uptake of glucose, fats, and amino acids for storage.
the sympathetic system suppresses insulin release from pancreas.
Glucagon
Released by the pancreas. has opposite effect as insulin on blood glucose levels. Glucagon stimulates release of glucose from the liver. Facilitate increase in blood glucose concentration.
Fast Acting hormones
Catecholamines, Insulin, and Glucagon
Cortisol
Released from adrenal cortex stimulates Free fatty acid mobilization and mobilized glucose symthesis in liver.
Slow acting, increases with exercise intensity and stresses on body. High cortisol levels occur after long duration events. High levels of Cortisol can cause protein breakdown and ketosis.
Growth Hormone
released from pituatary gland, plays major role in protein synthesis. Also supports action of cortisol.
Slow acting hormones
Cortisol and growth hormone
3 types of fuel during exercise
Carbohydrates, Fats, and Proteins.
Which macronutrient stored energy generated ATP anaerobically?
Carbohydrates. crucial for maximal exercise.
Carbohydrate is stored as what in muscle and liver?
Glycogen.
Glycogenlysis
Process where glycogen from liver is broken down into glucose and released into blood stream.
Blood glucose levels are regulated through glycogen stored where>
Liver
Low intensity exercise uses muscle glycogen or blood glucose?
Blood glucose plays larger role
High intensity exercise uses muscle glycogen or blood glucose?
muscle glycogen
first hours of submaximal exercise uses and remaining duration uses?
muscle glycogen, then blood glucose
during low intensity exercise what type of fat energy is used?
Circulating Free fatty acids from adipocytes.
At higher intensities, what type of fat is used for energy?
metabolism of muscle triglycerides.
At beginning of exercise FFA acids and Triglyceride usage is equal but as it progresses which takes over?
Plasma FFA takes over as fuel
Protein must be broken down into what before it can be used for fuel>
Amino Acid. Can come from Blood or muscle fiber itself to be used as fuel.
Glucose- Alanine cycle
glucose from non exercising muscles can be delivered indirectly to exercising muscles through this cycle.
Is Protein used for fuel during exercise?
Very rarely, during prolonged exercise there is a small increase in use.
What are the 3 energy system that contribute to total energy needs of body?
Phosphogen, Anaerobic, and aerobic
Phosphogen
onset of activity, or with increase in intensity.
Anaerobic System
During endurance activities before body achieves steady state. or during endurance activities when intensity approaches anaerobic threshold. fast, glycolic lactate system
Aerobic System
Also the oxidative system. Takes over when phosphagen and fast glycolic fatigue.
Cori Cycle
Cycle of lactate to glucose between the muscles and the liver.
Ability of skeletal muscle to contract depends on what 3 characteristics?
Maximal force production, speed of contraction, and muscle fiber efficiency.
Are fast twitch or slow twitch muscles produce more force?
Fast twitch muscle fibers produce 10-20% more force than slow twitch because of cross bridges.
Are fast or slow twitch muscle fibers more efficient?
Slow twitch fibers are more efficient than fast twitch due to higher concentration of myoglobin. They are more efficient at using oxygen.
Muscle fatigue is associated with
a Reduction in body’s glycogen reserves.
Radiation
Heat loss in the form of infrared rays, transfer of heat from one surface to another without physical contact. Ex. Sun’s rays
conduction
Transfer of heat from body into molecules of cooler objects that come on contact with surface. Ex. sitting on a hot metal chair
Convection
form conduction where heat is transferred to air or water molecules in contact with body. Ex. Wind from man blows on skin
Evaporation
Heat is transferred from the body to water on the surface of the skin.
How much fluid should you drink before, during, and after exercise?
2 hours Before: 500-600 ML (17-20 oz)
During- every 10-20 minutes drink 200-300 ml based on sweat loss(7-10 oz)
After- drink 450-675 ML for every .5 kg or 16-24 oz for every lbs.
Peripheral vasoconstriction
narrowing of artioroles, reduces blood flow to shell of body which decreases amount of body heat lost.
Nonshivering thermogenesis
stimulation of metabolism to increase internal heat production
Shivering
rapid involuntary cycle of contraction and relaxation of sketal muscles. Can increase body rate of heat production by 4-5 times.
SAID Principle
Specific Adaptions to imposed Demands
What happens to blood volume when exercise?
Increase in blood volume primarily in plasma with initial endurance training. Increase in plasma volume within one hour of recovery from first exercise. Most increase in blood volume is from Plasma, smaller amounts from red blood cells.
What happens to heart size when exercise
heart size and heart volume increase. Left ventricular cavity and thickening of walls. thickening of the wall is from resistance training and larger size is from endurance.
What is the Fick Equation
used to determine rate at which oxygen is being used during physical activity. Oxygen consumption is from Stroke volume and heart rate and difference in oxygen extracted.
When stroke volume increases, HR generally what
Decreases at rest
What happens to blood flow during exercise
Blood flow to active muscles is enhanced. New capillaries develop and existing become easier to use.
Blood Pressure during exercise
Both systolic and diastolic blood pressure is lowered in active individuals.
Oxidative enzymes during exercise
Increase in size and number of mitocondria within the skeletal muscles. Also increases activities of mitocondra.
All or none Principle
When activated all muscle fibers in a motor unit maximally contract simultaneously.
twitch
motor units smallest contractile response to a singal electrical simulation.
Summation
Series of multiple stimuli in rapid sequence resulting in greater force production.
Tatanus
peak force production of a motor unit.
How do hormonal changes effect hormones?
Catacholamines- Output declines during irst couple weeks.
Cortisol- slight increase during exercising.
Insulin- Maintain levels that are closer to resting level. normal decrease is reduced with training.
Glucagon- smaller increase in glucose levels, closer to resting rates.
Growth hormone- no effect on resting values and less dramatic rise during exercise.
Testosterone- increase if you do heavy resistance training.
Which of the following is NOT a method the body uses to preserve blood volume during steady-state exercise?
Increasing stroke volume
Why?
The following changes take place to preserve blood volume:
A progressive increase in heart rate at steady-state exercise to maintain cardiac output and offset the small decrease in stroke volume associated with the fluid lossA compensation in blood pressure via further vasoconstriction in the non-exercising regions to maintain peripheral resistance and blood pressureA release of hormones-antidiuretic hormone, or vasopressin, and aldosterone-to help reduce water and sodium losses from the body
What is the primary advantage of the increase in blood volume that results from chronic cardiorespiratory exercise?
Enhanced oxygen delivery to working muscles
Are the Receptors in the brain are the first to initiate changes in breathing.
True
If blood accumulates in the ventricles of the heart, the cardiac fibers will stretch, which will lead to an increased amount of blood being ejected during the contraction.
TRUE
Why?
An increase in ventricular volume at the end of the cardiac cycle stretches the cardiac muscle fibers, which improves the force of contraction. Consequently, a rise in cardiac contractility results in an increased amount of blood pumped per beat.
