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LACTATE - Friend or Foe of a Runner?

Updated: Sep 20, 2023

Runners talk about it all the time but how much do we really understand about it? In this blog we explore the pros and cons of getting your lactate levels to rise, with the help of coach and tutor Colin Lancaster, from the Lydiard Foundation, and Dr Keith Livingstone, author of Healthy Intelligent Training.

Lactate (or lactic acid) is a familiar term in the vocabulary of the running fraternity. You hear it coming out of runners’ mouths a lot. It’s something that they love to hate, and take great delight from stories about both succumbing to or overcoming it during a tough training session or race. 

There are those who love getting all sciencey about it too, wanting to know exactly where their lactate threshold is, and exactly how to format their hard interval session to improve it.  And there’s those that love to blind others with their science.

The science can be a bit complicated to be fair but, as the old saying (by songwriter Woody Guthrie) goes, “Any fool can make something complicated. It takes a genius to make it simple.”

I’m certainly no genius but I’m also gonna try not to be a fool, with these words, which I’ve put together with the aim of giving you some simple facts and, moreover, some practical advice which will help your training - hopefully. 

So, here goes…..

Firstly, what is lactate and is it a good thing or a bad thing? 

Before I start, you may notice I’ve used the term ‘lactate’ and not ‘lactic acid’.  For now, just take it they’re the same thing. I may explain more about it later.

Anyway, the first place most people look to find something out nowadays is Google. And for this subject, it’s actually quite a good starting point. Because if you search for the word ‘lactate’, the hits on the first few pages of results are probably not going to be about running. They’re more likely to be links to various medical institutions. 

The top hit when I Googled it just now was a website for laboratory tests, and gave advice on which diseases a lactate test can help detect.  

Second was an article from the Nursing Centre, which is quite informative but, as you start reading, quite alarming. 

In the very first paragraph you come across these words: ‘While working in the intensive care unit, checking a lactate level was routine. Unfortunately, an elevated lactate level is typically a bad sign for the patient, often related to increased organ dysfunction and mortality.’

And the subsequent Google hits continue along a similar path.

‘Okay, okay, so you’ve just written this to tell us that it’s a bad thing’ is probably what you’re now thinking.

Well, no, that’s not actually the case. Because, while I AM here to help you understand why and when it can be a bad thing for a runner, I’m also keen to explain why and when it can be a good thing…..because it can be that too. But, because of its bad sides, it needs to be used wisely. 

Personally, I like to think of lactate as a ‘Dr Jekyll and Mr Hyde’ type character because it has these two opposing sides to its character; one good, one bad.

Let’s talk about the good guy, Dr Jekyll, first, and how lactate is a good thing for a runner?

When our muscles aren’t getting enough oxygen - either because there’s a malfunction in our system or we’re working them hard - our bodies sense there is some kind of emergency going on. And as we become anaerobic (without oxygen) it asks for increased levels of lactate to start entering our bloodstream to provide additional energy. 

This boost of energy is there to help us out of the fix by enabling us to work harder to overcome the danger.  So, as an endurance runner,  this can be interpreted as a good thing, because it helps us to run faster.. 

When we push hard, and oxygen alone can’t hack it, this 'lactate energy system' kicks in, giving us valuable extra energy without the need for more oxygen. If we work it well, and push it close to the point where it would overcome us (i.e. our lactate threshold), it will keep us going at a decent pace for about an hour or so before we start to succumb to the discomfort of fatigue.  

Push too hard though and that hour soon becomes minutes or even seconds because the lactate will start to flood in quickly and, as a result, legs will become heavy and breathing laboured. We’ve all seen that 800 metre runner go from first to last on the second lap of a race for this very reason eh?!

The good news is that we can train our lactate system and, if we train it well, it can give us a valuable bit of extra speed in a race.  This could be an attractive proposition, as it could be just what you need to bring those PBs down a bit. 

There’s another good thing about training your body to use it’s lactate energy system too.  It can be done pretty quickly. You will have to work hard, with some pretty tough anaerobic training, such as interval sessions. But within a few short weeks, you’re likely to be seeing some improvement in your speed. 

Happy days, you may be thinking. Let’s crack on with some interval sessions and start bringing those PBs down! 

Chances are though, especially if you know me well, you’re more likely to be thinking there must be a ‘but’.  

Well, yeah, of course there is! And the guy with the big ‘but’ comes in the form of Mr Hyde. He’s lurking in the shadows waiting to shoot you down with that silver bullet you thought you’d discovered. In fact he’s got loads of bullets ready to flood your body with, in the form of hydrogen ions.

And it’s these pesky ions, which are the ‘emissions’ or waste products of the process, that give rise to the term lactic ‘acid’. Because it’s them that turn your bloodstream more acidic and make your muscles burn. The diagram below, courtesy of Dr Keith Livingstone (author of Healthy Intelligent Training), illustrates this and shows how it correlates with training intensity. (Note: Intensity percentages are based on Heart Rate Reserve, i.e. max - resting. Pulse rates shown are an example and will vary between individuals.)

© Dr Keith Livingstone

You see, the lactate isn’t an acid. As explained above, it’s a fuel - or energy source - for your body to use when it perceives things are going wrong. But when we demand our bodies to burn lots of it, there are more waste products - a bit like when we put our foot hard on the accelerator in a car. 

The turbo charger may kick in and give us a useful burst of speed, but it ain’t a great way to drive the car all the time. That’s because what is essentially an emergency mechanism is inefficient on fuel, and is going to wear out both engine and body parts much quicker. 

For these reasons I think it’s worth taking a moment to reflect on why the evolution of the human body, over millions of years, has led to us having the energy systems that we do. 

Our ancestors were hunter-gatherers so needed the ability to travel long distances on foot, often with scarce amounts of food and water. So they needed an energy system to allow them to go for hours, and sometimes days, at a time in search of sustenance. The aerobic energy system, which demands little more than oxygen, a little water and stored fat reserves, therefore evolved to support this. 

But occasionally they needed to move fast, to extract themselves from danger or capture an elusive prey. So an emergency ‘flight or fight’ system to use on such occasions was required too. Hence the lactate system evolved.   

We also have a third energy system, the alactic system, which acts as a kind of starter motor (more car analogies, sorry!) and gives us a few seconds of free energy. That’s probably a subject worthy of its own blog though, so I’m not going to cloud the issue with it here; other than to say the remarkable creature that is the human body is designed so that all its systems support one another and can work seamlessly together - transitioning from one to the other as and when necessary.

One of the main reasons the human species has survived and flourished on planet earth is this ‘system integration’. Because our ancestors relied purely on manual effort to live their lives day to day, their aerobic systems became very well developed and their bodies strong and robust. Which meant they could withstand the rigours of going hard and fast occasionally when the need arose, and recover from it quickly, ready for the next time the need to go fast came up. 

Imagine what might have been different if they’d sat in one place all the time waiting for the food to come past them. Chances are they’d tear a little used hamstring trying to sprint after it, or become prey themselves as their bodies are flooded by those pesky hydrogen ions all too quickly as they run away! And even if they survived, they’d be stiff for days, and praying that danger didn’t come their way again soon. 

Anyway, I digress. Or do I? Maybe it’s a good analogy, because when you look at why the world’s best endurance runners are as good as they are, a lot of their success is probably down to the fact that they live their lives like our ancestors in many ways, albeit without the spears.

Runners at all levels can learn a lot from how the elite endurance runners train. However, all too often, I see people trying to emulate their heroes without understanding the whole picture. Something that is often influenced by TV, podcast or magazine interviews when they are asked about the key aspects of their training, or that ‘killer’ interval session which led to the gold medal or world record. 

Invariably they talk about things that they did in the past few weeks, which put the icing on the cake that was their training.  Not the less glamorous stuff they’ve been doing for the previous decade or more, which are probably much more beneficial for a typical club or recreational runner. Things such as the high volume of easy aerobic running, keeping their bodies strong and flexible, eating well and sleeping lots. 

We’re not here to delve deep into that today though, as I’ve banged on enough about that in previous blogs.  

What I really want to do is give some insight into how - like those elite runners - you can be astute enough to take your favours from Dr Jekyl, while keeping Mr Hyde at bay. 

So firstly let’s understand, in practical terms, what happens when we do anaerobic training sessions which bring the lactate energy system into play. This is perhaps best done by summarising both the upsides and the downsides. 

Now let’s understand how we can get the most benefit from training our lactate system, as part of that ‘integrated system’ which is our body.  

This - at the risk of sounding like a Downing Street briefing - is about doing the right thing at the right time. 

The right thing is to be prudent with the amount of anaerobic training that you do to work the lactate system. And you may be surprised about how little is required to get the optimal benefit. Something which we’ll explore in a little more depth in a moment. 

The right time is to focus on anaerobic training at the correct time within your training programme, and only to focus on it for a few weeks. This should be after you’ve done sufficient training to optimise your aerobic fitness and prepare your musculoskeletal system, and at an appropriate time before your ‘A’ race. 

In terms of the volume of anaerobic training, it’s valuable to look at how much the elite runners do, who - pretty much without exception - have the Lydiard Training principles at the heart of the regimes. It’s also useful to realise that it is part of a training pyramid, and therefore proportionate to the overall volume of training (and rest/recovery) they are able to do. 

80/20 is often banded about as the optimal split between easy and hard running for endurance runners. But, as you’ll see from the charts below, which are courtesy of Colin Lancaster (coach and course tutor at the Lydiard Foundation), the proportion of anaerobic running is much smaller than 20%, even in the phase of training when that is the focus. So 20% is probably best thought of as the absolute maximum number of sessions that include ANY running that isn’t at an easy aerobic effort level.  For example, an anaerobic interval session may last around an hour in total but may only include 15-20 minutes of anaerobic running.  

Training paces within the Lydiard Pyramid

© Lydiard Foundation, Colin Lancaster

The bars on the chart represent the typical volume of training done at the various intensities during each phase of a Lydiard training cycle, working from bottom to top over a 5-6 month period.  Note: The ‘1hr cp’ (1 hour competition pace) is the effort level most runners can sustain for around an hour, often referred to as ‘lactate threshold’.

To train the lactate energy system, Colin and his colleagues at the Lydiard Foundation recommend anaerobic intervals at 5k race effort (e.g. 6 x 3 minutes), with sufficient recovery (e.g. 3 minutes) between each to allow the body to shift the accumulated lactate before the next effort.  

A very common mistake, however, is for runners to go too fast during the efforts, particularly during the early part of the session. Something which serves no purpose, other than to increase the level of fatigue and hence the recovery time. 

How often you should train anaerobically depends on the phase of training you are in and, critically, the overall volume of training you have built up to. This is because, as mentioned above, it should be proportionate to the aerobic training you do at a much easier pace. 

Elite level endurance runners rarely do so more than twice per week, as part of a regime that sees them running every day, and sometimes twice a day, with the vast majority being at an easy aerobic pace. So, to put things in perspective, if you run 3 or 4 times a week, including a weekly anaerobic interval session and going as hard as you can at parkrun every Saturday, you've probably got 5 or 6 weeks before your improvements plateau or you’ve picked up an injury. This is because you're training harder than an Olympian.

Reducing the amount of anaerobic running you do doesn’t necessarily mean you get less opportunities to run fast when training though. It just means you have to be prudent about how much you do and when you do it. And also find ways to run fast without having Mr Hyde round to visit! Something I’ll explore the options for in another blog.

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