W9 - Alkalisers & Buffering Agents Flashcards
What are the ways in which muscle can get rid of H+?
Monocarboxylase transporters (remove lactate + H from muscle)
Sodium-hydrogen exchanger
Sodium bicarbonate transporters
Why is bicarbonate important to bring into the muscle?
Due to it acting as a buffer to make the cell more alkaline
Why is bicarbonate important to bring into the muscle?
Due to it acting as a buffer to make the cell more alkaline
What is really important for membrane potential?
K+
Na+/K+ pump
3na+ OUT
2k+ IN
Accumulation of K+ outside cell with reduced membrane potential will cause
Issues with the ability to generate force
Effects of extracellular K+ on peak force
Increased extracellular [K+]
Less negative resting membrane potential.
Effects of extracellular K+ on peak force
4-7mM extracellular K+
not any real effect
Effects of extracellular K+ on peak force
10mM extracellular K+
25% loss of peak force.
Effects of extracellular K+ on peak force…
12mM extracellular K+
Inability to generate force.
What do buffering agents allow?
⬇️ in the increase of H+
⬇️ in the increase in K+
⬆️ lactate in venous blood (leaving tissues) but no change in arterial lactate.
What does supplementation of bicarbonate do?
⬆️ blood bicarbonate pools = more efficient buffering of the muscle due to bicarbonate soaking up the H+
When is supplementing sodium bicarbonate useful?
In high output, anaerobic glycolysis events
When the limitation could be due to low pH
For who is there greater effect of acute sodium bicarbonate supplementation?
In untrained athletes
Due to trained already exhibiting the adaptations i.e they would have more monocarboxylase transporters so already have an improved buffering capacity.
Chronic bicarbonate supplementation… What resulted in better maintenance of pH?
Medium + high intakes
Side effects to bicarbonate supplementation
Vomiting
Diarrhoea
Dizziness
G.I issues
When to take sodium bicarbonate supplementation and how much
0.3-0.5g/kg/BM
90-120 mins b4 exercise
What is carnosine?
Dipeptide in animal flesh
What is carnosine made up of
L-histidine (EAA) and beta-alanine (AA)
Purpose of carnosine
Buffers H+
Anti-oxidant
Can stop glycation + carbonylation
What % of muscle buffering capacity comes from carnosine?
15%
Can carnosine be absorbed whole?
NO
What can result in increased muscle carnosine conc?
Supplementation of b-alanine
Beta-alanine and HIIT training
Increased VO2 max and TTE at 3 weeks
Side effects to beta-alanine
Parathesia Double vision Hypertension Weight-gain Cognitive difficulties. — To overcome, slow release tablets?
