Lactate Threshold Testing

A couple of weeks back I was invited along by Pure Sports Medicine to take part in a Lactate Threshold test at their Bank Clinic.

I will be honest, I had heard about the test before, but I wasn’t 100% sure what I was going to have to do, or what it was going to tell me. But what I did know, is that it’s hard bloody work! And how did I know this? Because when I mentioned it to people I was getting it done the general response was to laugh, and then say Good Luck! Greaaaaaat, I was starting to wonder what I had let myself in for!

I received an email from Graham the morning of my test making sure that I wasn’t planning on running before or even running to the clinic (I’ll be honest, the thought had crossed my mind!) as the test works best when you are rested, and apparently us endurance runners have a habit of trying to fit runs in whenever we can (whoops!) but by doing so it can skew the results of the test. In an ideal world, I should have had a rest day the day before too, but luckily all I had done was a nice easy paced run so it didn’t have too much of an effect on the results.

I arrived at the clinic and met with Graham who talked me through what we were going to do, and then I had to sign my life away (no, literally!) The test was simple, I was going to be running on a treadmill for between 40-60 minutes, for blocks of time at various speeds, with the aim to increase the speed throughout until we found where my maximum pace was.

During the test both your heart rate (you are required to wear a heart rate monitor, but the clinic can provide one if you don’t have one) and bloods are monitored.

NB – your bloods are monitored by a small finger prick needle and then a sample is taken. This happens quite frequently throughout the test so if you have a real fear/issue with needles and/or blood then this test would not be a good choice for you!

So remember I said it was best to make sure you were completely rested? The reason for this is that lactate can stay in your blood for between 24-48 hours, so when my bloods were taken right at the start of the test, the count was a little higher than expected, but even after just doing a fast walk on the treadmill for a few minutes it returned back down to the ‘normal level’ as my body was able to process it back into fuel pretty quickly.

The test was broken up into approx 4 minute intervals. We started with just a fast walk for the first block and then gradually increased to a slow, comfortable jog. Also throughout the test, as well as monitoring my HR and bloods I also had to say how I felt on a scale of 6-20 in terms of effort (Rate of Perceived Exertion, with 6 being complete rest and 20 being maximum effort)

Graham then popped all of my results into a table which shows the speed of the treadmill (KM), my blood result, heart rate and finally my RPE score.

As you can see from my results, from around 30 minutes was where it was starting to get tough! And not only does my HR rise quite quickly, but so does the levels of lactate in my blood. Graham then made the call to stop the test during the last block as I had pretty much reached my maximum level, and I certainly don’t think I would have been able to run much faster for another 4 minute block!

I have to say, I was pretty relieved when it was finished! I had basically just done a pretty tough 40 minute progression run.. so much for it being my rest day!

Graham then briefly went over my results and assured me they were pretty good but that my full report would follow the following week, along with my prescribed heart rate training zones (the super duper important bit!). Here are my results.

So why is this important? Because quite simply, if you are working to heart rate it gives you the best idea of how hard your body is working, and how hard it should be working depending on the session you are doing and what you are looking to get out of it.

For example – the classic ‘Easy Run’ (which could be classed as Active Recovery or Endurance) Although technically it’s the simplest form of running, it can sometimes be the one that most people get wrong (and I have definitely been guilty of this in the past)

An easy run should be exactly what it says on the tin, easy! So although technically it might ‘feel easy’ for you to head out at your 5k pace every time you go for a run, if your HR is hitting that Zone 3-4 training zone during these runs, that my friend is not classed as easy! Using HR is a great way for you to know what level you should be working to on these runs so that you are not pushing your body too much when it’s simply not needed.

So what is Lactate Threshold and why is it good to know what yours is?

Have you ever had that feeling during a race or a really hard training session where all of a sudden it’s like someone has flicked a switch and your legs go from feeling pretty good to really heavy and that burning sensation? Yes? Well, that’s all down to Lactic acid!

Your body is constantly producing lactic acid whilst exercising, but when it gets to that point it’s where your body is unable to keep up with how much is being processed, and basically can’t get rid of it! Your body/brain/everything will be trying to do what it can to get you to slow down, and this can also be described as ‘hitting the wall’ – an experience unfortunately most of us will encounter during a race.

Knowing what your ‘Lactate Threshold’ pace is has many benefits. It means that during your training, you can push your body to that limit, and like with anything, if you keep working at it, you can improve it! And then hopefully you will be able to replicate it on race day and be able to push that little bit harder, or hold on for longer.

Here is my personalised report based on my test results.

“Aerobic Threshold was achieved at 14 kph and 168 bpm. This is the threshold of “mouth-closed” training. Anything above that and you are accumulating substantial lactate but are able to re-process it back into fuel. You can maintain this speed for 3+ hours and gives you a good marathon pace to be focussing on if one completes a marathon at this sort of time.

For yourself, it should be somewhat faster to achieve marathon pace. Lactate Threshold was achieved at 16.5kph (3:38min/km) and 181 bpm. This is the threshold by which you are accumulating considerable lactate and your body cannot keep up with how much is being processed. This pace can be kept for approx. 1 hour if conditions were perfect.

My recommendation for YOUR improved lactate – prescribe some of your tempo runs at 3:55min/km pace and kick to 3:30min/km for a time of 10% of total duration (e.g 60min run = sets of 6 mins). Work at a EASY:HARD ratio of 1:1.”

Since the test, I have been paying a lot more attention to my HR during training. At the moment I have been focusing a lot more on working in my ‘Aerobic Zone’ due to my upcoming ultra marathons, and it has honestly made such a difference. Although I have been running more miles than ever before, the majority of my runs have been at ‘easy pace’ – meaning that I haven’t felt burnt out and I also seem to be recovering well in between sessions.

Soon enough though, my training for New York marathon will be officially kicking off, and I am really looking forward to using this information to make sure this is my best training block yet. I won’t be second guessing what paces I need to run at, and I will know exactly how hard I need to work in certain sessions to see results. I’m actually pretty excited!!

Whether you are looking for that marathon PB, or perhaps you are newer to running, I believe there are benefits to having the test done. For beginners, one of the most common mistakes they make is pushing themselves too hard, too quickly. And it’s easily done! You feel great when you first start running regularly and it’s all to easy to head out on every single training run and try to run quicker than before, or race parkrun every single week.. but unfortunately, this will catch up with you! So if you know how hard you should be working from the start, over time you will have a much more productive (and probably enjoyable!) running journey.

I hope you found this useful, and if you do decide to get yourself booked in for a test…. GOOD LUCK!

Jordan xx

Pure Sports Medicine are offering 20% off your Lactate Threshold Test (usually £146) if you quote ‘projectmarathongirl’ when booking until 26th July 2019. To book directly please email

Or to find out more information you can click here to head straight to the website.

Session was gifted as part of ongoing partnership with Pure Sports Medicine.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s