Week 10 - Buffering agents (NOT IN EXAM) (Beta-alanine) (Sodium bicarbonate) Flashcards

1
Q

What is the background behind the use of buffering agents?

A

 High rates of glycolysis during
maximal intensity exercise leads to
the accumulation of H+.
 Fall in intramuscular pH from ~7.1
to <6.5 (blood pH decreases from
~7.4 to 7.1).
 Acidosis inhibits glycolysis (PFK),
reducing ATP production, causing
fatigue.
 Various buffers minimise shift in pH.

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2
Q

What is beta-alanine?

A

is a (non-essential) beta amino acid precursor of carnosine

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3
Q

What is carnosine?
- Where is it found?
- What does it have an important role in?
- What foods is it found in?

A

Carnosine is a dipeptide made up of two amino acids beta-alanine and histidine
- Carnosine is found in human skeletal muscle
- Has an important role as intracellular pH buffer
- Carnosine is found in red meat, chicken and fish and seafood.

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4
Q

How long is beta-alanine supplementation required to achieve meaningful increases in muscle carnosine levels?

A

4 weeks

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5
Q

True or False:
Diet alone is enough to increase muscle carnosine levels required for a performance benefit.

A

False - requires supplementation of beta-alanine

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6
Q

What forms are beta-alanine available in?

A

powder or tablet/capsule forms
- Slow release capsules can help to improve retention, further increasing muscle carnosine levels.

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7
Q

How does chronic beta-alanine supplementation improve performance?

A

Increases muscle carnosine levels which enhances intracellular buffering of H+ ions produced during anaerobic glycolysis.
Greater muscle buffering capacity can limit/delay fatigue and improve exercise performance when exercise is limited by muscle acidosis.

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8
Q

Describe the “loading dose” supplementation regime.

A

3.2 g beta-alanine/day for >8 weeks
OR
6.4 g beta-alanine/day for >4 weeks

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9
Q

Describe the “maintenance dose” supplementation regime.

A

1.2g beta-alanine/day

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10
Q

What are the benefits of consuming beta-alanine in split doses with meals?

A

enhanced uptake and better management of side effects

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11
Q

When should you consider the use of beta-alanine supplementation?

A

 Short (30 sec to 10 min), sustained high-intensity sports e.g., rowing, track cycling, swimming, middle distance running.
 In the weeks preceding a period of
training where training intensity is
prioritised, or before competition blocks.
 Sports that involve repeated high-intensity efforts e.g., resistance training, team/field sports, racquet sports.

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12
Q

How can the response to beta-alanine vary between individuals?

A

Baseline muscle carnosine levels
- Athletes who follow a plant-based diet may have lower levels of muscle carnosine and therefore further room for improvment.

Training status
- Highly-trained individuals may experience smaller benefits from beta-alanine supplementation. However, this can still be worthwhile for athletes where small benefits can have a meaningful impact on sporting results.

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13
Q

What side effects can beta-alanine have?

A

Acute doses of instant release beta-alanine exceeding 800-1000mg can result i8n paraesthesia (tingling sensation, like pins and needles) on the skin that can last up to an hour and/or skin rashes.

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14
Q

What other important considerations are there with beta-alanine supplementations?

A

Economic cost: it requires a substantial investment given the long period of supplementation.

Inaccurate claims: inclusion of beta-alanine in common pre-workout supplements may contain an amount that is too small to have any effects on performance despite giving you a “buzz”.

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15
Q

What is the current recommended loading dose for beta-alanine?

A

3.2-6.4g of beta-alanine per day for >4-8 weeks

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16
Q

How can we minimise side effects such as paraesthesia and skin rashes?

A

slow-releasing capsules or consuming the supplement in split doses, or consuming with meals

17
Q

What is sodium bicarbonate?

A

It’s a blood (extracellular) buffer which plays an important role in regulating blood and muscle pH.

18
Q

What are the effects of sodium bicarbonate?

A

Decrease blood and muscle acidosis during anaerobic exercise.
This reduces fatigue and increase muscle metabolic function and exercise capacity (anaerobic).

19
Q

What is the (acute) supplementation protocol for sodium bicarbonate?

A

200-300mg/kg BM sodium carbonate 2-3h before exercise
with 10mL/kg BM fluid + 1.5g/kg BM CHO

20
Q

How should we consume sodium bicarbonate?

A

slowly - 30-60mins to avoid GI symptoms

21
Q

What is the primary side effect associated with sodium bicarbonate?

A

gastrointestinal upset including nausea, stomach pain, diarrhoea and vomiting.

22
Q

Explain the split dose strategy to sodium bicarbonate supplementation.

A

several smaller doses giving the same total intake over a time period of 60-180mins

23
Q

Explain the serial loading strategy to sodium bicarbonate supplementation.

A

3-4 smaller doses per day for 2-4 consecutive days prior to an event

24
Q

When should we consider the use of sodium bicarbonate?

A

 High-intensity events (1-7 min) where muscle acidosis causes fatigue e.g., rowing, swimming, middle distance running.
 High-intensity, endurance sports (>1 h) where a surge or sprint/climb to the finish may be required.
 Sports involving prolonged repeated high-intensity bouts e.g., team sports, racquet and combat sports.
 Can be used to enhance training capacity and training adaptations when training is characterised by any of the above characteristics.

25
Q

What are potential safety concerns with sodium bicarbonate?

A
  • GI distress (nausea, stomach pain, vomiting) therefore several trials before any competition and individualization of supplementation strategy is recommended.
  • Potential for weight gain due to fluid retention.
  • Contamination: athletes should only use batch-tested supplements.
26
Q

What are other buffering alternative to sodium bicarbonate?

A

beta-alanine or sodium citrate