384 final exam Flashcards
At rest, how is 100% of ATP produced?
aerobic metabolic pathway
What are low during rest?
blood lactate levels
resting O2 consumption in L/min
0.25 L/min
Rest to exercise transition ATP increases or decreases how
increases immediately
Rest to exs oxygen uptake
increases rapidly
In rest to exs transition, oxygen uptake increases rapidly how?
Reaches steady state within 1-4 minutes, and after steady state is reached, atp requirement is met through aerobic ATP production
In rest to exs transition, oxygen uptake increases rapidly how?
Reaches steady state within 1-4 minutes, and after steady state is reached, atp requirement is met through aerobic ATP production
Rest to exs, initial ATP production is through
anerobic pathways
Oxygen deficit
lag in o2 uptake at the start of exs until steady has been achieved
Who has a lower O2 deficit?
trained subjects
Why do trained athletes have a lower o2 deficit?
Better developed aerobic bioenergetic capacity due to cardiovascular or muscular adaptations, which results in less production of lactate and H+
Recovery from Exs, o2 uptake remains what above rest into recovery?
elevated
The higher intensity, the what
more oxygen needed in recovery
o2 debt
repayment of o2 deficit at onset of exercise; used to resynthesis PC to make ATP later
EPOC
excess post-exs o2 consumption
EPOC terminolgy reflects that ~
20% elevated o2 consumption used to “repay” o2 deficit
EPOC terminolgy reflects that ~
20% elevated o2 consumption used to “repay” o2 deficit
EPOC
rapid and slow portion of O2 debt
Rapid portion of o2 debt
resynthesis of stored PC, and replenishing muscle and blood o2 stores
slow portion of o2 debt
Elevated HR and breathing = increased energy need
Elevated body temp = increased metabolic rate
Elevated E and NE = increased metabolic rate
Conversion of Lactate to glucose called gluconeogenesis
EPOC is greater following
higher intensity exs
Why is EPOC is greater following higher intensity exs?
Higher body temp
greater depletion of PC since additional o2 is required for resynthesis
Greater blood concentrations of lactate and H+ creates greater level of gluconeogenesis
Higher levels of blood E and NE, returns homeostasis quickly after exs
Why is EPOC is greater following higher intensity exs?
Higher body temp
greater depletion of PC since additional o2 is required for resynthesis
Greater blood concentrations of lactate and H+ creates greater level of gluconeogenesis
Higher levels of blood E and NE, returns homeostasis quickly after exs
Removal of lactate and H+ following exs classical theory
majority of La converted to glucose in liver
Removal of lactate and H+ following exs recent evidence suggests
that 70% of LA is oxidized by LDH and used as a substrate by heart and skel msucle, and 20% is converted to glucose by the liver
Removal of lactate and H+ following exs recent evidence suggests
that 70% of LA is oxidized by LDH and used as a substrate by heart and skel msucle, and 20% is converted to glucose by the liver
Type I and IIa fibers like
pyruvate going to Acetyl CoA in krebs
Removal of lactate and H+ following exs recent evidence suggests
that 70% of LA is oxidized by LDH and used as a substrate by heart and skel msucle, and 20% is converted to glucose by the liver, 10% converted to AAs
Type I and IIa fibers like
pyruvate going to Acetyl CoA in krebs
LA is removed how
more rapidly with light exs in recovery
optimal intensity for LA removal is ~
30-40% VO2max
Prolonged exercise is >
10 min
Prolonged exercise ATP production is primarily from
aerobic metabolism
prolonged exs steady state oxygen uptake can generally be
maintained during submax exs via oxidative phosphorylation
Prolonged exs in a hot/humid environment or at high intesity upward what
drift in o2 uptake over time, therefore steady state is typically not achieved due to body temp and rising E and NE
O2 uptake increases how unitl
linearly until maximal o2 uptake (VO2max) is reached, and no furhter increase in vo2 with increasing workrate
VO2max is a what? affected by what 2 things?
Physiological ceiling for delievery of o2 to muscle, and is affected by genetics and training
Physiological factors influencing VO2max include
maximal ability of Cardiorespiratory sys to deliever o2 to muscle, and ability of muscle to use oxygen and yield ATP aerobically
what is Lactate threshold?
LT is the point at which blood lactate rises systematically during incremental exs
LT appears at
~50-60 VO2max in untrained subjects, and at higher work rates for trained ~ 65-80% vo2max
LT aka
Anaerobic threshold or OBLA (Onset of blood lactate accumulation)
LT is when blood lactate levels reach
4 mmol/L
LT is when blood lactate levels reach
4 mmol/L
Explanations for the LT
Low muscle o2 (hypoxia), accelerated glycolysis, recruitment of fast-twitch fibers, and reduced rate of lactate removal
Why does accerlated glucolysis explain LT
NADH produced faster than it is shuttled into mitochondria, and excess NADH in cytoplasm converts pyruvate to lactate
Why does recruitment of fast-twitch fibers explain LT
LDH isozyme in fast fibers promotes lactate formation
Why does recruitment of fast-twitch fibers explain LT
LDH isozyme in fast fibers promotes lactate formation
2 practical uses of LT
1) Prediction of performance combined with VO2max
2) Planning Training programs becuase its a marker of training intensity and one could choose a HR based on LT
DOMS occurs
24-48 hours after exs
Does Lactate cause muscle soreness?
Phsyiological evidence does not support this claim since lactate removal is rapid 60 minutes follwoing exs
Power athletes should experience what after eeveery workout?
DOMS
What is rare following routine workout?
muscle soreness
What causes muscle soreness?
Microscopic injury to muscle fibers leads to inflammation?
What causes muscle soreness?
Microscopic injury to muscle fibers leads to inflammation?
Low intensity exercise uses what primary fuel?
Fats are fuel for
High intensity fuel source
Carbs >70%vo2max
Crossover concept
Describes the shift from fat to CHO metabolism as exs intensity increases due to recruitment of fast muscle fibers and increasing blood levels of E
Crossover concept
What is it and how it does this?
Describes the shift from fat to CHO metabolism as exs intensity increases due to recruitment of fast muscle fibers and increasing blood levels of E
Is low intensity exs best for burning fat?
no
At low intensity (~20%vo2max, a blank
high percentage of EE (~60%) derived from fat, however, total energy expended is low, so total fat oxidation is low as well
At higher intensities,
lower % of energy ~ 40% from fat, but total EE is higher and total fat oxidation is higher as well
Prolonged low intensity results in what and how?
shift from carbs metabolism toward fat metabolism due to an increased rate of lipolysis, which is the breakdown of TG to glycerol and FFA via enzymes called lipases that are stimualted by rising blood levels of E
Fats burn in the flame of
carbs
Why does fat burn in a carb flame?
Glycogen is depleted during prolonged high intensity exs in muscle and liver. This results in a reduced rate of glycolysis and production of pyruvate when carb stores become depleted, which cause reduced Krebs cycle intermediates due to hindered glycolysis. This will cause reduced fat oxidation since fats are metabolized by Krebs cycle.
Why does fat burn in a carb flame?
Glycogen is depleted during prolonged high intensity exs in muscle and liver. This results in a reduced rate of glycolysis and production of pyruvate when carb stores become depleted, which cause reduced Krebs cycle intermediates due to hindered glycolysis. This will cause reduced fat oxidation since fats are metabolized by Krebs cycle.
During endurance exs what contributes to fatigue?
Depletion of muscle and blood carbs stores contributes to fatigue.
Ingestion of carbs can
improve endurance performance during submax (90 min) exs
How grams of carbs are required per hour?
30-60 g carbs/ hr
Carbs during performane may improve
performacne in shorter, higher intensity events as well
Muscle glycogen is the primary source of
carbs during high intensity exs
Muscle glycogen supplies much of
the carb in the first hour of exs
Blood glucose is from
liver glycogenolysis
Blood glucose is primary source of
carbs during low-intensity exs
blood glucose is vital during how long as
long duration exs as muscle glycogen levels decline
Sources of Fat during EXS
Intramuscular TGs
Plasma FFA
sources of carbs during EXS
muscle glycogen
blood glucose
sources of carbs during EXS
muscle glycogen
blood glucose
Intramuscular TGs are primary source of
fat during higher intensity exs
Plasma FFA is from
adipose tissue lipolysis, which is when TGs breakdown into glycerol and FFA
Plasma FFA is from
adipose tissue lipolysis, which is when TGs breakdown into glycerol and FFA
FFA is converted to
Acetyl-CoA and enters Krebs cycle
PRimary source of fat is during
low-intensity exs
FFA becomes more vital as muscle TG levels do what for what
decline in long-duration exs
FFA becomes more vital as muscle TG levels do how for what
decline in long-duration exs
FFA becomes more vital as muscle TG levels do how for what
decline in long-duration exs
Source of Protein during exs
Proteins broken down by AAs
Muscle can directly do what
metabolize BCAAs and alanine
Liver can convert what AA to glucose
alanine to glucose
Liver can convert what AA to glucose
alanine to glucose
Protein break down to AAs is only a
small contribution ~2% to total energy production during Exs, and may increase 5-10% late in prolonged duration exs
Proteases
Enzymes that degrade proteins
Proteases are activated when?
in long-term exercise
Proteases are activated when?
in long-term exercise
Lactate can be used as a blank and how so?
fuel source by skel muscle and the heart by being converted to pyruvate which is converted into acetyl-CoA and enters krebs cycle
lactate can be converted to what in liver, what is this called
glucose in liver = gluconeogenesis/ Cori cycle
lactate can be converted to what in liver, what is this called
glucose in liver = gluconeogenesis/ Cori cycle
Lactate shuttle is when
lactate produced in one tissue and transported to another
Explain Cori Cycle
Lactate is produced by skel muscle and is transported to liver. Liver converts lactate to glucose called gluconeogenesis, and glucose is transported back to muscle and used as a fuel.
Explain Cori Cycle
Lactate is produced by skel muscle and is transported to liver. Liver converts lactate to glucose called gluconeogenesis, and glucose is transported back to muscle and used as a fuel.
R =
VCO2/VO2
R for palmitic acid (FFA)
0.70
R for carbs/glucose =
1.00
