Week 10 - Buffering agents (NOT IN EXAM) (Beta-alanine) (Sodium bicarbonate) Flashcards
What is the background behind the use of buffering agents?
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.
What is beta-alanine?
is a (non-essential) beta amino acid precursor of carnosine
What is carnosine?
- Where is it found?
- What does it have an important role in?
- What foods is it found in?
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.
How long is beta-alanine supplementation required to achieve meaningful increases in muscle carnosine levels?
4 weeks
True or False:
Diet alone is enough to increase muscle carnosine levels required for a performance benefit.
False - requires supplementation of beta-alanine
What forms are beta-alanine available in?
powder or tablet/capsule forms
- Slow release capsules can help to improve retention, further increasing muscle carnosine levels.
How does chronic beta-alanine supplementation improve performance?
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.
Describe the “loading dose” supplementation regime.
3.2 g beta-alanine/day for >8 weeks
OR
6.4 g beta-alanine/day for >4 weeks
Describe the “maintenance dose” supplementation regime.
1.2g beta-alanine/day
What are the benefits of consuming beta-alanine in split doses with meals?
enhanced uptake and better management of side effects
When should you consider the use of beta-alanine supplementation?
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.
How can the response to beta-alanine vary between individuals?
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.
What side effects can beta-alanine have?
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.
What other important considerations are there with beta-alanine supplementations?
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”.
What is the current recommended loading dose for beta-alanine?
3.2-6.4g of beta-alanine per day for >4-8 weeks
How can we minimise side effects such as paraesthesia and skin rashes?
slow-releasing capsules or consuming the supplement in split doses, or consuming with meals
What is sodium bicarbonate?
It’s a blood (extracellular) buffer which plays an important role in regulating blood and muscle pH.
What are the effects of sodium bicarbonate?
Decrease blood and muscle acidosis during anaerobic exercise.
This reduces fatigue and increase muscle metabolic function and exercise capacity (anaerobic).
What is the (acute) supplementation protocol for sodium bicarbonate?
200-300mg/kg BM sodium carbonate 2-3h before exercise
with 10mL/kg BM fluid + 1.5g/kg BM CHO
How should we consume sodium bicarbonate?
slowly - 30-60mins to avoid GI symptoms
What is the primary side effect associated with sodium bicarbonate?
gastrointestinal upset including nausea, stomach pain, diarrhoea and vomiting.
Explain the split dose strategy to sodium bicarbonate supplementation.
several smaller doses giving the same total intake over a time period of 60-180mins
Explain the serial loading strategy to sodium bicarbonate supplementation.
3-4 smaller doses per day for 2-4 consecutive days prior to an event
When should we consider the use of sodium bicarbonate?
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.
What are potential safety concerns with sodium bicarbonate?
- 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.
What are other buffering alternative to sodium bicarbonate?
beta-alanine or sodium citrate
