Chapter 5 (energy) Flashcards
How do you measure indirect calorimetry? what values are attained from the machine and how are they converted to acquire Co2 and oxygen production?
From the machine measurement you will be provided with total expired air and the fraction of co2 and oxygen in it. O2 and Co2 fractions in inspired air are known fractions and the haldane transformation solves the missing piece of the puzzle. Since nitrogen concentrations do not change you can use that to determine the volume of inspired air.
what is RER? what does it tell me? what is it for carbohydrate v.s fat metabolism?
RER is Co2 produced divided by oxygen utilized. Carbs is usually 1.0 and fats is usually .7. Calculating the number will tell you what percentage of fats v.s carbs are being used for energy.
what is the average RER?
.8 or .3 ml.min
Limitations of indirect calorimetry?
can only be used during aerobic activites. does not include protein. Can be off sometimes bc byproducts of energy metabolsm release co2 that adds to total expired air. This co2 is not being used by the muscle but the equation will indicate it is.
define metabolic rate?
rate at which body is using energy
1 L of oxygen equals how many kcals?
5 kcals
Difference between basal metabolic rate and resting metabolic rate?
both indicate the energy expended when at rest. Resting metabolic rate has less requirments so it will be used more often.
What is a big factor in basal metabolic rate?
fat free mass. women will have a lower rate bc they have less fat free mass
relationship between basal metabolic rate and Vo2
the volume of O2 measured will indicate how much oxygen is being consumed by the body which will indicate how much substrate is being used by the body for energy. This can then be converted to kcals which will tell you how many kcals the body is using during any activity
Describe the “slow component”
It is when Vo2 increases after body has surpassed lactate threshold. This happens because the bodys main fibers are fatigued and the body has to rely on less efficient fibers. Forces more energy to be used since the fibers are less efficient
Describe VO2 drift?
It is when VO2 increases below lactate threshold but when exercise intensity is long. This happens because the main type II fibers are tired and it has to use IIx. (less efficient) could also happen bc the rate of breathing increases (more O2 going in to be used). breathing harder for more air
What is VO2 max?
the max amount of oxygen your body can take up before a plateu occurs. It is a good indicator or aerobic fitness not necessarily performance. This is hard to measure bc muscles will give up before you can reach limit
what is VO2 peak?
Max amount of vo2 taken up during an exercise. can be seen when intensity increases no longer correspond with oxygen uptake increase
What makes a good endurance runner?
they can use opperate using a higher percentage of VO2 max for a longer time
Difference between absolute and relative VO2 consumption?
relative is more specific to body type L/min v.s ml/kg/min
what does MET measure?
how much energy you are using compared to rest. 1 met = 3.5 ml/kg/min.
How does anaerobic metabolism affect measurements?
you can not seperate the two. You are never using 100% of either system.
what are two ways to estimate anaerboic metabolism contributions?
lactate threshold and estimated post-exercise oxygen consumption
describe EPOC?
at the begining of the exercise you will be using anaerobic metabolism. Your body will be in an oxygen deficit. This deficit will be made up at the end of exercise. You can measure it by determining how much extra oxygen you are consuming (heavy breathing) compared to normal after exercise
Describe how lactate threshold helps measure anerobic contribution?
lactate will be created during anaerobic metabolism to get ride of extra hydrogen. if you figure out how much lactate is produced you can figure out how long you were using anaerobic glycolysis
After intense exercise, EPOC occurs what is the order in which stores are replenished?
fast component: PCr stores replenished
Slow component: lactate is converted back to glycogen
Clearance of co2
No real way to measure the capacity your body has to anaerobic metabolism
maybe by o2 deficit
describe what the economy of effot means?
how well your body can perform the exercise. more training= better economy of effort, body gets better are producing effort at the pace you need
What are the top four indicators of performance?
High Vo2 max
High lactate threshold (body clears lactate fast)
High economy of effort
Large amount of type II fibers
what is fatigue?
body must decrease performance bc body can not keep up. unable to continue at the same intensity
what are the main causes of fatigue?
inadequate energy, byproducts, neuromuscular function, mind
how does inadequate Pcr cause fatigue?
if you do not pace yourself body will quickly deplete Pcr, will not have energy have to move onto something else
what is an indicator of glycogen depletion
glycogen stores are empty
what causes glycogen stores to be depleted?
the fiber recruited first will deplet the fastest, then you have to rely on less efficient fibers. Different exercises rely on different body parts, those specific body parts will run out of glycogen. The body will steal glucose from the blood causing hypoglycemia (more fatigue)
negative affects seen after glycogen depletion?
Nadh cant be produced, ETC cant occur, calcium isnt released
general result of glycogen depletion?
the body will resort to fatty acid metabolism which is slower and less efficient
how does phosphate accumulation cause fatigue?
it will hurt calcium release which is needed for muscle contraction
How does hydrogen ion accumulation cause fatigue?
hydrogen ion concentrations will cause lactate and bicarbonate to form which is good but they are not enough to keep ph from lowering. at lower ph body will inhibt PFK and hurt calcium release AND Decreases sensitivity to calcium
what is neuromuscular fatigue?
when the body can not stimulate the muscle to contract
what are some causes for neuromuscular failure?
ach is not released, cholinesterase either breaks down too much ach or it doesnt breakdown enough (muscle cant relax), potassium escapes the cell, hyperpolarizing, GABA inhibits the potential
How does the Central nervous system affect fatigue?
the central governor will signal to the body to slow down
when does muscle damage occur?
when you are doing an activity the body isnt used to
what are the two causes of muscle damage?
eccentric contractions (in every movement and are susceptible to damage). the electron transport chain produces free radicals which breakdown the cell membrane
Why is critical power important?
it is the balance between exercise duration and intensity. Might be the reason why marathons cant be done under an hour. Body is incapable of pushing the limits of intensity and duration at the same time
what are the two types of muscle soreness?
acute (minutes to hours) and doms (days)
what are the causes of acute muscle soreness?
accumulation of metabolic byproducts and swelling
what are the causes of doms?
muscle damage
Explain the steps the body undergoes when damage (DOMS) occurs?
damage occurs, calcium is disturbed, zdisks and titin are broken, neutrophils produce inflammation, macrophage picks up debris, satellite cells come in a replace damaged cells (hypertrophy)
Affects of DOMS on performace
damage to z-disks, and calcium distrubtion causes a decrease in force production
how do you prevent DOMS?
start at lower intensities and progress slowly
what are the two types of cramping?
excercise associated and heat
describe how exercise associate cramping occurs?
muscles are fatigued, the body excites spindles and ibhibits GTO. this causes spastic contractions (cramping). To stop this you must activate GTO which will inhibit contraction (done by stretching)
why do heat cramps occur?
electrolyte loss through sweating. sodium is lost, this makes the cell easily excited which causes more signals to go through (Cramping)
