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Why does lactic acid build up in muscles?

Getting the best out of you.

In an earlier chapter we touch on the three energy systems and how they work. One of the more noticeable actions our body makes is when it reaches anaerobic threshold! If you’re not sure what we’re talking about it’s the moment when your legs and arms start to go heavy, you lose much of your ability to perform at the same level and the longer you go the quicker you drop off. We’re going to explain a little bit of the science behind it and see if there’s anything we can actually do to prevent or hold off the effects of Anaerobic Threshold, lactate.

As discussed earlier, mitochondria are responsible for 95% of our bodies energy source and whilst they develop at an incredibly high rate, they’re not always capable of keeping up with the intensity of the exercise and the amount of pyruvate being produced. As this occurs, the pyruvate gets converted to lactate roughly 10-90sec into high intensity exercise and significantly high levels of hydrogen ions spill into the blood stream which signals the beginning of the end. More commonly known as Anaerobic Threshold.

What do we have to do to prevent us from reaching anaerobic threshold? Well simply, don’t train at high intensity right? That’s the easy way to avoid it but will we ever improve with that attitude? probably not. In fact you’re more likely to become unfit, reach your anaerobic threshold earlier and find a simple walk up hill physically challenging, leaving you back on the couch and struggling to move (worst case scenario).

So what can we do? Well we can do a few things actually. We can add high intensity exercise in short bursts that will over time increase our ability to run faster or lift heavier for longer. Running is probably something that a lot of our clients can relate to. A simple 5km run isn’t so simple for everyone and yet when they turn on the TV and watch a bunch of athletes essentially sprint around a track and complete it in 12:30min, a pace that they would struggle to match for 50-100m and whilst exhausted they still have energy for a celebration lap. This has happened over time, they’ve worked hard, pushed their body to their limits so that running sub 3min pace is no longer considered intense enough to bring on anaerobic threshold.

For those of us that would like to train to get fitter and not necessarily become an Olympic athlete, or reach your personal best, we have a simple answer that may be a little harder to master. Knowing your ability is important, but not as important as pacing yourself just beneath your anaerobic threshold. This will allow you to reach your personal best without “burning out” too early. Almost too simple right?

Hope this helps you understand a little bit about lactate (not breast milk) and its effect on the body.

Justin Beard Pn1


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