Fast Talk, ep. 30: Myth Busters: Why we can’t talk about lactic acid

For the longest time, we thought lactic acid made our legs burn when we rode hard. It turns out that was wrong.

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The VeloNews Fast Talk podcast is your source for the best advice and most interesting insight on what it takes to become a better cyclist. Listen in as VeloNews columnist Trevor Connor and editor Caley Fretz discuss a range of topics, including training, physiology, technology, and more.

Ouch, it burns! But what is “it” — the root cause of the pain in your legs when you smash it up a hard climb? For the longest time, we colloquially called “it” lactic acid. It turns out that was wrong.

Coach Trevor Connor and Caley Fretz examine the chemistry that occurs in our muscles while riding and racing. They talk to Dr. Iñigo San Millán, who is the director of Colorado University’s exercise physiology lab. Best of all, they give you practical advice for your own training to help make that burn go away — or at least make you faster even if it hurts.

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(Benton, et al., 2008; Bonen, 2001; Cairns, 2006; Gladden, 2001; Green, et al., 2002; Mainwood & Renaud, 1985; Messonnier, et al., 2013; San-Millan & Brooks, 2017; Thomas, Bishop, Moore-Morris, & Mercier, 2007; Thomas, Bishop, Lambert, Mercier, & Brooks, 2012; van Hall, 2010)

Benton, C. R., Yoshida, Y., Lally, J., Han, X. X., Hatta, H., & Bonen, A. (2008). PGC-1alpha increases skeletal muscle lactate uptake by increasing the expression of MCT1 but not MCT2 or MCT4. Physiol Genomics, 35(1), 45-54. doi: 10.1152/physiolgenomics.90217.2008
Bonen, A. (2001). The expression of lactate transporters (MCT1 and MCT4) in heart and muscle. Eur J Appl Physiol, 86(1), 6-11. doi: 10.1007/s004210100516
Cairns, S. P. (2006). Lactic acid and exercise performance : culprit or friend? Sports Med, 36(4), 279-291.
Gladden, L. B. (2001). Lactic acid: New roles in a new millennium. Proc Natl Acad Sci U S A, 98(2), 395-397. doi: 10.1073/pnas.98.2.395
Green, H., Halestrap, A., Mockett, C., O’Toole, D., Grant, S., & Ouyang, J. (2002). Increases in muscle MCT are associated with reductions in muscle lactate after a single exercise session in humans. Am J Physiol Endocrinol Metab, 282(1), E154-160.
Mainwood, G. W., & Renaud, J. M. (1985). The effect of acid-base balance on fatigue of skeletal muscle. Can J Physiol Pharmacol, 63(5), 403-416.
Messonnier, L. A., Emhoff, C. A. W., Fattor, J. A., Horning, M. A., Carlson, T. J., & Brooks, G. A. (2013). Lactate kinetics at the lactate threshold in trained and untrained men. [Article]. Journal of Applied Physiology, 114(11), 1593-1602. doi: 10.1152/japplphysiol.00043.2013
San-Millan, I., & Brooks, G. A. (2017). Reexamining cancer metabolism: lactate production for carcinogenesis could be the purpose and explanation of the Warburg Effect. [Review]. Carcinogenesis, 38(2), 119-133. doi: 10.1093/carcin/bgw127
Thomas, C., Bishop, D., Moore-Morris, T., & Mercier, J. (2007). Effects of high-intensity training on MCT1, MCT4, and NBC expressions in rat skeletal muscles: influence of chronic metabolic alkalosis. Am J Physiol Endocrinol Metab, 293(4), E916-922. doi: 10.1152/ajpendo.00164.2007
Thomas, C., Bishop, D. J., Lambert, K., Mercier, J., & Brooks, G. A. (2012). Effects of acute and chronic exercise on sarcolemmal MCT1 and MCT4 contents in human skeletal muscles: current status. Am J Physiol Regul Integr Comp Physiol, 302(1), R1-14. doi: 10.1152/ajpregu.00250.2011
van Hall, G. (2010). Lactate kinetics in human tissues at rest and during exercise. [Review]. Acta Physiologica, 199(4), 499-508. doi: 10.1111/j.1748-1716.2010.02122.x

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