Lactate testing

Lactate threshold test, Friday 13th, January 2017
Today I went over the road from my office to a sports testing clinic, and tried to find out what my lactate threshold is.* There are various other tests of fitness you can do, including VO2max, which allegedly has a testing protocol similar to “Do things as hard as you possibly can, until you vomit into a dustbin. Then stop.” Lactate threshold testing isn’t as glamourous, because (as it turns out) there’s less need to be sick into a bin, which is clearly the main motivation people have for doing anything sporty.

It’s actually a little bit boring, as well as slightly painful (the perfect combination of lunchtime activities?) I thought hitting golf balls at a driving range wasn’t the most entertaining pursuit, but it’s the height of cultural endeavour compared to running on a treadmill where the only view is a concrete wall on the other side of the window of the room you’re in. Plus every five minutes you stop running and give some blood, and then start running again.

Not, happily, that it’s death by a hundred pricks. I was expected to get jabbed with a needle every five minutes, but instead they poke you with a spike (similar in pain to putting a staple into your fingertip) once, and then every five minutes massage and squeeze your finger until a dot of blood seeps out, and then put that into the testing unit. So all that remained was to run and run and run, and get hotter and hotter (it’s incredible that the disgusting heat and humidity of Singapore is preferable to running in an air conditioned room with a fan blowing on you, but I suppose that’s the wonder of physics and volumes of air flow.

Now, with VO2max (I think) you keep going until you max out. With lactate threshold, they’re just looking for you to hit 4 mmol/litre. Which you hit just at the point things start to get a little grim on the treadmill (for me, about 30 minutes, and 14 km/h) rather than when you’re at key vomit inducing pace.

Then you stop, and you cool down, and then you look at the results and figure out what that tells you.

In my case, it turns out that my threshold is at 162 bpm – the same as what TrainingPeaks had guessed at, but it’s nice to have this confirmed in laboratory conditions rather than have an algorithm guess at it – and the graph at the top allows you to figure out what level of exertion your runs should be at. Don’t forget, most of your workouts should be in the comfortable zone where you’re clearing lactate faster than you’re producing it. I think that’s where I am right now, so the lactate test becomes a confirmation that I’m doing things right, just as much as a way to train. Since I’m four weeks into my current training plan, I’m not going to switch away from power, but it’s interesting to compare these different approaches.

(Also, due to a configuration setting, I failed to log my power for this test, so I don’t have a clear comparison of power zones vs lactate threshold defined zones. Yet.)

As it’s only half an hour, I can go and get tested again just before the marathon, and then we’ll see if I was hopelessly optimistic with my target time or not. Given that I can (according to this test) run at 13 km/h a 3:15 marathon would be on the cards. If we could flatten Singapore and install air conditioning throughout the route, and everyone else would just get out my way, please. So it will be interesting to see how things turn out.

I had my test at Coached, and the facility itself is fairly basic – there’s a treadmill, and some fans, and some chairs to sit at afterwards to discuss the results – but honestly that’s what you need. There’s no need when you’re collecting data to gold plate the environment itself. Although the sports scientist did raise his eyebrows when I told him my goals for the year are a marathon and an 800m race. Dumb is as dumb does…

* In layman’s terms, your lactate threshold is the point at which exercise gets really horrible; below this, your body is capable of clearing out the waste products that exercise produces, faster than they get made. Above this point, your muscles are pumping out lactate faster than your metabolism can clear it, and you start to feel very unhappy. You can express it either in terms of how fast you have to go (unhelpful if you don’t spend all your time on the same treadmill) or in your heart rate (which also has some issues, I suppose…)


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