Tuesday, July 31, 2012

Lactic Acid De-mystified

As an athlete you probably associate lactic acid with that burning sensation you get in your muscles when you push your body to it's limits.  This is a common misconception, in fact, lactic acid does not even exist in the body.

What your body does produce naturally is lactate and it is considered a main energy source for hard working athletes.  Lactate production in the muscles accumulates rapidly when the energy demands of your body outstrip the supply of available oxygen; this means that muscle carbohydrate breaks down without oxygen but this does not cause the body pain.

There are quite a few misunderstandings regarding lactate and it's role in the body, so let's clear a few things up:
  • Lactic acid is not responsible for delayed onset muscle soreness (DOMS), instead this is the result of small tears in the muscle that occur while exercising
  • Once lactate is formed, it can serve as a source of energy to the muscles, also known as the 'lactate shuttle system'
  • It does not cause fatigue, it actually happens to be a useful and efficient fuel source
  • Lactate is the most important contributor to the making of glucose in the liver (Gluconeogenesis)
  • Lactate is actually metabolized within a couple hours of exercise
  • It is not an athletes enemy
This topic is still highly debated and the role of lactate or 'lactic acid' is just one aspect of the many common myths surrounding health and exercise.  With the abundance of information available to us it can be confusing to sort out the good information from the bad; so if you happen to stumble onto some seemingly crazy claim, remember to look for studies to support what the author is saying or at least have reputable sources with cited experts who can be tracked down. 

References from the SIRC Collection:

1. A Closer Look at Blood Lactate Threshold. Running & Fitnews. March 2011;29(2):15-17.
2. Beneke R, Leithäuser R, Ochentel O. Blood Lactate Diagnostics in Exercise Testing and Training. International Journal Of Sports Physiology & Performance. March 2011;6(1):8-24.
3. Brooks G. The lactate shuttle during exercise and recovery. / Le va et vient du lactate lors de l'exercice et de la recuperation. Medicine & Science In Sports & Exercise. June 1986;18(3):360-368.
4. MacIntosh B, Esau S, Svedahl K. The lactate minimum test for cycling: estimation of the maximal lactate steady state. / Test du minimum de lactate en cyclisme: estimation de l'etat d'equilibre maximal du lactate. Canadian Journal Of Applied Physiology. June 2002;27(3):232-249.
5. Saunders P. Energy systems & lactate thresholds. Run For Your Life: R4YL. August 2007;(13):14-15.
6. Wagner P, Lundby C. The Lactate Paradox: Does Acclimatization to High Altitude Affect Blood Lactate during Exercise?. Medicine & Science In Sports & Exercise. May 2007;39(5):749-755.