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So it turns out reading Harry Potter can teach us a fair bit about sports science, who knew? Many characters in the series are not actually what they have been built up to be, none more so than Severus Snape. Throughout the books Snape is characterised as a villain, becoming more and more aligned with the death eaters and Voldemort, only to be revealed as one of the series’ most misunderstood heroes. If that statement has somehow spoiled the books for you I want to make it clear I make no apologies, the last book was published in 2007, at this point, it is on you.
So how does this convoluted metaphor relate to sports science? Well, picture this: you’re midway through a gruelling marathon, your legs feel like lead, and all you can think about is the dreaded lactic acid build-up. But what if I told you this ‘enemy’ is an unsung hero? For years, sports commentators have painted lactic acid as the villain, the ‘enemy’ athletes must battle, causing many a nerd-induced meltdown amongst exercise physiologists. The reason for these meltdowns is firstly that the commentators are likely using the wrong term, instead of lactic acid they really mean lactate. Secondly, and crucially, lactate is not the bad guy after all it’s more like a misunderstood genius, often blamed but seldom appreciated.
Throughout several blog posts I am going to explain to you what lactate is, common misconceptions, measuring lactate to dictate your training zones and how this can ultimately inform your training and develop your race plans. Let’s start from the beginning with how lactate was discovered and its journey from villain to hero over decades of research.
The journey of lactate discovery dates back to the early 18th century. In 1780, the Swedish chemist Carl Wilhelm Scheele first identified it in sour milk, leading to its name. It wasn’t until the 1920s that Otto Meyerhof, a German physiologist, and Archibald Hill, a British physiologist, made groundbreaking advances in understanding lactate’s role in muscle metabolism during exercise. Their work was so important that they shared the Nobel Prize in Physiology or Medicine in 1922.
For decades, lactate was dismissed as a mere waste product of anaerobic metabolism. This view persisted for decades, influencing training and recovery strategies among athletes, and still to this day is a commonly held belief. However, research in the latter half of the 20th century began to challenge these notions. Contrary to the myth, lactate itself isn’t what causes muscle fatigue; rather, it’s more likely due to a host of other factors including the accumulation of inorganic phosphate, hydrogen ions, and adenosine diphosphate.
During exercise, particularly at a high intensity, your muscles demand a lot more energy, leading to increased lactate production. This is just one reason why it will starts to accumulate in the blood. During exercise, we also see changes in hormones that constrict blood vessels, leading to a reduction in lactate clearance and recruitment of fast twitch muscle fibres which rely on lactate-producing energy generation.
Lactate is a major energy source during endurance activities. It was previously thought that lactate only starts to be produced under anaerobic conditions, however more recent research has shown it is continuously produced and utilised by muscles and other tissues even under fully aerobic conditions. On top of this lactate can travel to other muscles, such as your heart, or your liver, where it’s turned back into energy yielding pyruvate or glucose through a process called the Cori cycle. This shuttle mechanism allows lactate to be used as fuel by various tissues, enhancing overall energy availability.
Lactate may also be part of the reason why you get fitter in response to your training. Regular exposure to lactate through training sends signals to your cells which promotes adaptations including mitochondrial biogenesis, which is an increase in the number and efficiency of mitochondria. The more mitochondria you have and the better they work means more energy for you to fuel those all important PBs. Other reported training adaptations to repeated lactate exposure include improved efficiency in lactate clearance and utilisation, which also contributes towards better performance and quicker recovery.
Unlike the sudden twists and turns we see in the fictional stories the title of this article was based on, it’s taken decades of research to establish the role lactate plays in endurance sports, and no doubt we will continue to learn and adapt our advice as more research is published. Over time lactate has emerged from the shadows, not as a waste product, but as a vital fuel. Its journey from misunderstood villain to crucial ally should serve as a testament to the evolving nature of sport and exercise science. Far from being the enemy, lactate plays a crucial role in energy production during exercise.
Now we have an understanding of lactate’s role in energy production, stick with me for future articles on lactate thresholds, how they are measured, what they mean and whether everyone should be measuring blood lactate to inform their training.
