W2-L1: Lactate Flashcards
3 energy systems
(power and capacity)
What is Lactate?
Lactate is a byproduct of anaerobic metabolism, produced when glucose is broken down for energy without sufficient oxygen, commonly during intense exercise.
What are the benefits of lactate?
3
- Lactate is a readily combustible fuel
- Lactate serves as a precursor for gluconeogenesis or glycogenesis
- Can be reused to create pyruvate and produce more ATP
LACTATE AND EXERCISE
Why does lactate accumulate during exercise?
(Hint: Rate of Appearance vs. Rate of Disappearance)
3
- During intense exercise, lactate production increases due to accelerated glycolysis and the recruitment of fast-twitch muscle fibers, which rely on anaerobic metabolism.
- The sympathetic NS also induces vasoconstriction, reducing blood flow to tissues that normally help clear lactate.
- As a result, the rate of lactate appearance exceeds its rate of disappearance, leading to an accumulation of lactate in the blood.
How does blood lactate increase?
What enzyme is responsible for lactate production?
Blood lactate accumulates only when its disappearance by oxidation of substrate conversion does not match its production
High levels of lactate dehydrogenase in fast-twitch muscle fibers convert pyruvate to lactate.
Why is there higher levels of lactate dehydrogenase in fast twitch fibers?
High levels of lactate dehydrogenase (enzyme) in fast-twitch muscles fibers favor to convert pyruvate - > lactate.
Opposite for slow twitch muscle fibers.
how does Lactate accumulation differ in trained vs untrained individuals?
Untrained Individuals: Lactate accumulation begins at a lower intensity (~50% VO₂ max).
Trained Individuals: Lactate accumulation starts at a higher intensity (~75% VO₂ max), indicating better efficiency in lactate clearance.
What is used for long term energy?
LONG-TERM ENERGY: THE AEROBIC SYSTEM
What is happening to lactate during steady state?
During steady state or steady rate, any lactate produced either oxidizes or reconverts to glucose.
Therefore, no appreciable blood lactate accumulated under steady-rate, aerobic metabolic conditions.
larger O2 defecit
theoretically could stay at steady state forever
What is the oxygen defecit?
Oxygen debt is the amount of extra oxygen the body needs to restore itself to its pre-exercise state after physical activity.
expresses the difference between the total oxygen consumption during activity and the total that would be consumed had steady rate oxygen consumption been achieved at the onset
What is OXYGEN CONSUMPTION (VO2)?
Capcity to take in, transport, and use oxygen
- can be used to approximate metabolic rate, the rate at which our body uses energy
- L/min or mL/kg/min
- calculated using the Fick Principle
Fick Principle
check notes
VO2 =
What is the oxygen debt?
Following physical activity, bodily processes do not immediately return to resting levels
Oxygen debt or recovery oxygen consumption or excess postexercise oxygen consumption (EPOC): total oxygen consumed in recovery minus the total oxygen theoretically consumed at rest during the recovery period
explain
lag before oxygen gets to working tissue on the onset of excersize
OXYGEN CONSUMPTION FOLLOWING EXERCISE
Oxygen Deficit:
During the initial phase of exercise, oxygen supply lags behind the demand, creating an oxygen deficit.
Steady-State VO₂:
Represents the equilibrium where oxygen supply meets the energy demand during moderate exercise.
EPOC (Excess Post-exercise Oxygen Consumption):
The additional oxygen consumed following exercise to restore the body to its pre-exercise state. EPOC is divided into rapid and slow components, addressing different physiological processes like replenishing ATP stores, removing lactate, and restoring oxygen levels in blood and muscle.
explain
slow and fast component
read textbook
EPOC following exhasutive excersize.
