Flashcards in Chapter 7,8,9,18 Deck (57):
how does lactate threshold differ in trained vs untrained
untrained at 55% Vo2max
trained at higher %
what are the two substances pyruvate can go to
lactate (w/lactate dehydrogenase) and acetyl coa (w/pyruvate dehydrogenase)
what is the definition of lactate threshold ?
% Vo2max when blood lactate starts accumulating
what will pyruvate become at 25, 55, and >55% VO2 max ?
at 25%, most pyruvate goes to Acetyl CoA
sufficient O2 to do this work
at 55%, increasing carb consumption, more pyruvate being formed, more of it goes to lactate
at >55% lactic acid accumulation, going to different organs but also a larger percentage of acetyl coA
what is the traditional explanation of blood lactate accumulation ?
relative tissue hypoxia. with imbalance between hydrogen release (from NADH) and oxidation, the hydrogens will instead bind to pyruvate to become lactate
where does lactate go at rest or in moderate exercise ?
oxidizes, converts to glucose, or synthesizes to amino acids (no net lactate accumulation)
list three factors that contribute to a higher lactate threshold
genes (fiber type, blood flow)
local training adaptations that favor less lactate production
greater rate of lactate removal
list 5 training adaptations in aerobic exercise
increase in mito size and number
increase in protein synthesis (for oxidative enzymes)
increase in effectiveness of these proteins, which yields more H+ and therefore more ATP
less lactic acid buildup due to better lactic acid removal
increased capillary density
why does it take time to reach steady state VO2 ?
time constraint for cells to use O2 being delivered.
how do untrained vs trained differ in reaching steady state Vo2 ?
trained reach it faster
what does the steady state represent ?
plateau in O2 consumption curve (balance between energy required and ATP produce)
no lactate accumulation during steady state.
what is oxygen deficit ?
the area from 0 to steady state
trained has smaller deficit than untrained
basically difference between total O2 consumption and the O2 that would have been consumed if we had SS all along.
what are the two factors that good endurance performance depends on ?
ability to deliver O2 and ability to use O2
what happens after you've reached Vo2 max and you keep going ?
using up any glycogen left for 15-20s
how does O2 consumption increase with each steady state "hill" ?
at first it augments rapidly, but then as you increase, it will barely increase, that's when you know the max is near
what are the 5 factors that need to be integrated for a good oxygen system ?
aerobic metabolism, pulmonary ventilation, hemoglobin concentration, blood volume and cardiac function, peripheral muscle and blood flow.
how does pulmonary ventilation affect the oxygen system.
Va/Q ratio = alveolar ventilation / pulmonary blood flow
should be 0.8
low capability of Va = low ability to reach an elevated Vo2
is a Va/Q of 0.8 always good ?
nope. sometimes the ratio is ok but the numerator and denominator are both very low (like in cardiac + pulmonary disease)
what is the Fick equation ? what does it imply ?
Vo2= Q x (a-v O2 difference)max
Q= cardiac output (HRmax x SVmax)
what is normal and max stroke volume? what does it depend on ?
normal 60-70 ml/beat
max 120-140 ml/beat
depends on left ventricle contraction
how does blood hemoglobin concentration affect oxygen use and transport
better capacity to transport O2 to tissues
what are the norms for Hb
women 13-15 g Hb/100 ml blood
men 15-17 g Hb/100 ml blood
what 2 illnesses cause low Hb
anemia (women 12, men 14)
multiple myeloma 8-10g Hb / 100 ml blood
lead to fatigue
what will happen with high Hb
17-20 g Hb/100 ml blood
when body is under high stress eg high altitude, increased blood viscosity
where can pyruvate get converted to glycogen ?
ONLY IN THE LIVER FOR THE LOVE OF KANYE
what tissues take up lactate
ALLLLLL OF THEM
what is EPOC
excess post exercise oxygen consumption
in mild aerobic activity, how much time does complete recovery take ?
2-4 min (fast component)
in moderate to heavy activity, what are the two components in EPOC ?
what are the three factors contributing to the slow component in EPOC ?
- thermic effect (temperature elevation, increased metabolic effect)
- hormone levels (E, NE) go to baseline after 30-40
- lactate removal
how fast O2 levels go to normal depends on two things what are they ?
intensity and duration of exercise.
how long can recovery O2 consumption last for (due to the slow component) in EPOC in supramaximal exercise ?
what 7 factors that contribute to EPOC ?
1- resynthesizing ATP and PCr (payback to exercising muscles)
2- resynthesizing lactate to glycogen to restore levels
3- oxidizing the rest of the lactate
4- restoring O2 and myoglobin to blood
5- restore thermogenic effect
6- restore catecholamine levels
7- restore physiologic functions like HR
what kind of recovery is best to restore blood lactate concentration to normal during EPOC ?
active recovery at 35-65% Vo2max
any higher and you'll be producing more lactate, so there's just going to be more to get rid of
how do you find carb RQ ?
C6H12O6 + 6 O2 --> 6 CO2 + 6 H20
6 CO2/6 O2= 1.00
how do you find fat RQ (eg palmitic acid)?
C16H32O2 + 23 O2 --> 16 CO2 +16 H2O
16 Co2/23 O2 = 0.7
what is the approximate RQ for protein ?
at rest what is the approximate ml/ min of O2 and CO2 ?
215 ml/min LCO2 and 250 ml/min L O2
how is RQ different from RER ?
RER is used when the ratio is bigger than 1 because the CO2 produced is higher than what metabolism is producing. (eg in hyperventilation).
explain where and how, in intense exercise or respiratory maneuvers, more CO2 appears
H-lactate + NaHCO3 (sodium bicarbonate) --> NaLa + H2CO3
H2CO3 is carbonic acid, a strong acid that goes to the pulmonary capillaries in the blood and in a special reaction that can occur only there H2CO3--> H2O + CO2 w/ the help of carbonic hydroxylase
5 factors that affect total energy expenditure
1 physical activity
2 diet induced thermogenesis
3 calorigenic effect of food on metabolism
to measure basal metabolic rate, what would we have to do ?
no falling asleep
is resting metabolic rate a relative value ?
what is bigger BMR or RMR
what is 1 MET
3.5 ml O2 /kg*min
or 5 kcal/ L O2
what are the two organs that consume the most oxygen
liver and brain
what is diet induced thermogenesis
results energy required to digest and stuff + energy from SNS activation and stimulation
does physical activity increase diet induced thermogenesis
how does climate affect total daily energy expenditure ?
RMR higher in tropical than in cold countries
how does pregnancy affect total daily energy expenditure ?
added energy cost from walking etc due to additional weight transported.
what is avg kcal expenditure for men and women
what are the 4 characteristics of fast twitch muscle fibers
- high capacity for transmission of AP
- high myosin ATPase activity
- rapid Ca2+ release and uptake by sarcoplasmic reticulum
- high rate of crossbridge turnover
what are the 4 characteristics of slow twitch muscle fibers
- low myosin ATPase activity
- slow calcium handling ability
- not as good glycolytic pathway
- large and numerous mitochondria
what is PGC-1alpha responsible for ?
promotes mitochondrial biogenesis, fatty acid oxidation, and hepatic gluconeogenesis. therefore if it's activated in genes there will be an increased proportion of type I muscle fibers
what does a skeletal muscle fiber consist of ?
the rest is stuff
a muscle's hydrogen consumption increases up to ... times in exercise