Science and cycling: β-alanine supplementation

Those of you who keenly watch some of the great sporting events on TV, like the Olympic Games or the Tour de France, will likely have heard the TV “experts” commenting on the build-up of lactic acid in an athlete’s muscles as they struggle to maintain performance. In fact, as I watched Sir Bradley Wiggins smash the hour record the other week, the commentator made reference to exactly this. This accumulation of lactic acid supposedly contributes to the individual’s discomfort; struggle to maintain performance and will eventually lead to total fatigue. However, lactic acid exists only momentarily in muscle and immediately dissociates to its constituent lactate ions and hydrogen ions (H+), rendering what these commentators say as incorrect. Perhaps what they mean is lactate, and although it was initially considered to be a waste product contributing to fatigue, the opposite is now considered true: evidence has shown lactate to be capable of moving between cells to be used as a fuel (Brooks, 2000). It is actually the accumulation of H+ in the working muscle that can be an issue, increasing muscle acidity, potentially reducing muscle function and thereby contributing to a reduction in an individual’s performance. Therefore, an intervention to combat the accumulation of H+ may improve exercise capacity and performance that is limited by muscle acidosis.

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The Grimace: not due to lactic acid accumulation

Muscle pH is maintained by a combination of intracellular (muscle) and extracellular (blood) buffers which can accept or release H+ to prevent changes in pH. Carnosine is found in human skeletal muscle and is made up of two constituent amino acids; histidine and β-alanine. The various roles of carnosine in muscle are debated, though its role as an intracellular pH buffer is undisputed; its ability to accept H+ thereby limiting/delaying muscle acidosis means it can be an important compound during exercise. It is known that β-alanine is the rate limiting factor to carnosine synthesis, and that supplementation in doses from as little as 1.6 g/day can increase muscle carnosine within two weeks (Stellingwerff et al., 2012). Subsequently, an increase in muscle carnosine will lead to an increased intracellular buffering capacity, theoretically contributing to an improved performance during exercise limited by muscle acidosis.

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​The synthesis of carnosine in muscle (the imidazole sidechain is where the H+ is buffered)

So can β-alanine improve cycling performance? I think the general answer to that question is yes. In the laboratories I have worked in at Nottingham Trent University and University of São Paulo, we have shown improved exercise capacity and performance during short duration single-bout high-intensity cycling (Sale et al., 2011) and repeated-bout high-intensity cycling (Painelli et al., 2014). There is also emerging evidence to suggest that 4 km time trial (TT) may be improved with β-alanine (Bellinger et al., 2015, conference presentation). The evidence regarding endurance cycling is unclear, and at first glance, unimpressive. There was no effect of β-alanine supplementation on 1 h cycling TT performance (Chung et al., 2014) or a 20 km cycling TT (James et al., 2014). However, these results should not completely deter the longer distance cyclist. There is evidence to suggest sprint performance following prolonged intermittent cycling can be improved with β-alanine supplementation (van Thienen et al., 2009). Therefore, the likely mechanism through which increased carnosine improves exercise means that individuals may benefit from β-alanine supplementation during more intense periods of cycling, such as sprinting or climbing, where increased muscle acidosis may be a limiting factor to performance. Importantly, the study by Painelli et al. (2014) showed similar improvements with β-alanine between trained and non-trained cyclists, suggesting performance improvements are not just limited to the elite athlete. So go ahead, pop those pills as the chances are pretty high that the guy overtaking you at breakneck speed is too. As for the elites, they take it as a staple in their diet.


Cutting edge research with highly trained cyclists (!)

On a personal (and much less scientific) note, I have taken β-alanine on several occasions while taking part in research studies, and I love the stuff. Although a contribution may have been psychological (note: I didn’t know if I was on the good stuff or placebo at the time so could never be 100% sure what it was), I felt great when taking it and my cycling statistics certainly reflected a benefit, with my average speeds increasing by several km/h every time I was on the supplement. Sometimes it’s important to look at the raw data, since most people rarely feel anything when on the supplement. Remember the wise words of Greg Leman, “it never gets easier, you just go faster.”