9) **** Lactate **** Flashcards
Where does Lactate come from?
? production of lactate is associated with Hydrogen (H+) ion production
Glycolytic production of lactate is associated with Hydrogen (H+) ion production
Glucose -> 2lactate + 2(H+) + 2ATP
Glycogen -> 2 lactate 1(H+) + 3ATP
Hydrolysis of ATP (ATP + H2O -> ADP + P + H+) requires water
H+ ions produced -> Metabolic Acidosis (If aerobic, these H+ ions will be removed // no O2 = metabolic acidosis)
What enzyme converts Pyruvate to Lactate?
Lactate dehydrogenase
Lactate dehydrogenase is responsible for?
Conversion of pyruvate to lactate
True or false:
Lactate is a waste product of anaerobic metabolism which gives rise to fatigue and mm pain
False
Metabolic fuel continuously formed and utilized even under fully aerobic conditions
Why might metabolic acidosis occur?
Hydrogen ions produced during the non-MIT Hydrolysis of ATP
ATP + H2O -> ADP + P + H+ (requires water)
H+ ions produced -> Metabolic Acidosis (If aerobic, these H+ ions will be removed // no O2 = metabolic acidosis)
Lactate removal after intense exercise
SLIDE 5 Lactate is removed more rapidly with ? recovery?
active or passive?
Lactate is removed more rapidly with active recovery?
Active Recovery (cooldown):
Optimal intensity: ~30-40% of VO2max (low intensity so as not to increase lactate) - must be low enough that energy is fully coming from aerobic metabolism
Most lactate is removed within 60-100min regardless of recovery method
- Passive recovery: 2hrs to fully recover
- Active recovery: 50 mins to fully recover
Lactate removal after intense exercise
SLIDE 5 Lactate is removed more rapidly with active Recovery
- Optimal intensity of ~30-40% of ?
Active Recovery (cooldown):
Optimal intensity: ~30-40% of VO2max
- low intensity so as not to increase lactate
— must be low enough that energy is fully coming from aerobic metabolism
Most lactate is removed within 60-100min regardless of recovery method
- Passive recovery: 2hrs to fully recover
- Active recovery: 50 mins to fully recover
Lactate removal after intense exercise
SLIDE 5 IMAGE Lactate is removed more rapidly with active Recovery;
Why is an intensity of ~30-40% of VO2 max optimal for Lactate removal?
Active Recovery (cooldown):
Optimal intensity: ~30-40% of VO2max
- low intensity so as not to increase lactate
— must be low enough that energy is fully coming from aerobic metabolism
Most lactate is removed within 60-100min regardless of recovery method
- Passive recovery: 2hrs to fully recover
- Active recovery: 50 mins to fully recover
Uses of lactate
SLIDE 7 What happens to most (70%) of lactate produced?
70% of lactate is converted back to pyruvate to enter aerobic metabolism
- Occurs in same cell if intensity of exercise decreases (MM catches up)
- Otherwise == Lactate Shuttle -> wherein lactate is transported to another cell or tissue with a lower rate of lactate production to be used for fuel (MCT proteins)
SLIDE 7 What type of proteins function as Lactate Shuttles?
Monocarboxylate transporter (MCT) proteins
- facilitate the mvmt of lactate between cells and tissues and within cells
Lactate moves from the cell/tissue from which it was produced to another with lower rate of lactate production
- From fast twitch (type II) to slow twitch (type I; oxidative) MM fibers
- To heart and brain
Uses of lactate
What happens to the lactate that isn’t converted back to pyruvate?
- 10% converted to?
- 20% converted to?
What happens to the lactate that isn’t converted back to pyruvate?
- 10%: converted to amino acids
- 20%: converted to glucose in the liver (cori cycle) and kidney
What happens to the lactate that isn’t converted back to pyruvate?
- 10%: converted to ?
- 20%: converted to glucose in the ? and ?
What happens to the lactate that isn’t converted back to pyruvate?
- 10%: converted to amino acids
- 20%: converted to glucose in the liver (cori cycle) and kidney
Increased blood lactate levels downregulates ?
Increased blood lactate levels downregulates FFA and glucose utilization as energy substrate
- downregulate so as to promote the use of LACTATE (thus decreasing lactate accumulation)
What happens to lactate that enters the mitochondria?
Lactate in the peroxisome?
Lactate in the mitochondria is converted to pyruvate
Peroxisome -> breaks down lactate
Lactate produced via ? in muscles is transported to the liver and converted to ?
Lactate produced via Anaerobic Glycolysis in muscles is transported to the liver and converted to Glucose (Gluconeogenesis)
- glucose returns to muscles and is metabolized back to lactate (cycle continues until MM metabolism decreases and lactate stops being produced)
Gluconeogenesis -> generation of glucose from non carbohydrate sources
What is the Lactate threshold?
Lactate threshold is the exercise intensity or relative intensity at which blood lactate begins to increase above baseline concentration
- Point at which during incremental exercise lactate production exceeds the rate of lactate clearance (removal)
What is Onset of Blood Lactate Accumulation (OBLA)?
OBLA -> occurs at higher relative exercise intensities where lactate production exceeds at a rate which it cannot be broken down; occurs where blood lactate reaches 4.0mM
Second inflection point on graph
Beyond OBLA lactate levels will increase drastically
In an untrained individual when does the Lactate threshold begin relative to VO2max?
LT begins at 50-60% of VO2max
- aerobic training can increase this percentage (lactate training)
