6. Lactate, The Fate Of Lactate & Thresholds

Question 1

Features of aerobic training?

Answer 1

• improved central (brain, organs) & peripheral (skin, muscles) blood flow
  -Enhances capacity of muscles fibres to generate ATP

Question 2

Features of anaerobic training

Answer 2

• increased short-term, high intensity endurance capacity
  -Increased anaerobic metabolic function → rate of ATP ( PC & muscle glycogen)
  -Increased tolerance for lactic acid during nigh intensity effort
• increased ability to utilise, tolerate & clear accumulation of metabolic waste
• associated with developing strength, speed & power

Question 3

Anaerobic threshold definition

Answer 3

The point where the body switch from aerobic to anaerobic metabolism

Question 4

Aerobic threshold definition

Answer 4

The point where the body switches from anaerobic to aerobic metabolism

Question 5

Lactate threshold definition

Answer 5

The point at which, during incremental exercise, lactate builds up in the bloodstream at a level higher than resting values.
Often around 1 mmol/L above baseline

Question 6

OBLA definition

Answer 6

Onset of blood lactate accumulation (lactate turn point)
Usually at 4 mmol/ L
Point there is a distinct, sudden & sustained increase in blood lactate

Question 7

What effect does training have on OBLA?

Answer 7

-Increased lactate threshold -athlete can perform at higher intensity before lactate accumulation begins to increase significantly
-Improved lactate clearance
-Greater aerobic capacity

Question 8

Benefits of training near the anaerobic/ lactate threshold (UCB)

Answer 8

Body is able to:
- improve its use of lactate as an energy source (via cori-cycle)
-Improve its clearance mechanisms
-Improve the buffering capacity to negate
The fatiguing effects of metabolic waste products

Question 9

What are the immediate physiological effects of the accumulation of lactic acid within the working muscle?

Answer 9

-↑ H+ concentration (pH↓)
-Muscle fatigue & discomfort
-Impaired ATP & glycolysis production
- oxygen debt (EPOC)

Question 10

What is the cori-cycle?

Answer 10

Lactate produced by anaerobic glycolysis in the muscles moves to the liver & is converted to glucose to be used as an energy source

Question 11

What is the overall fate of lactate?

Answer 11

1. 50 -75% pyruvic acid/ pyruvate oxidised into CO2 & H2O (enters mitochondria, used in kreb’s cycle and electron transport chain)

2.10-20% pyravic acid converted into glucose & glycogen to be stored in muscles & liver (via cori - cycle)

3. 5-10% converted into protein
4. Some converted into sweat & urine