Lactate Threshold Testing
The funnest, most difficult training session of my life
I had never wheezed during a workout before.
It was the final segment of the lactate threshold test that my wife had gotten me for Christmas (you’re right, we did have a surprisingly strange, unplanned, “healthy” Christmas this year).
Coach Dayna told me I was doing great — “Looking good Stephen, just 60 more seconds!” I couldn’t breathe. My arms were tingling from my hands up to my elbows. My feet were somehow still thudding on the treadmill. I kept going. What seemed like an eternity passed. I looked down at the timer. Surely I was almost finished. Only 10 seconds had gone — 50 seconds left.
“Am I going to pass out?”
What is lactate and why does it have a threshold?
“Lactation begins as early as a few weeks into the second trimester of (a) pregnancy.”
No no — not that kind. When you exercise, the cells in your muscles produce lactic acid, or “lactate” in the muscles when they consume carbohydrates.1 I’m not a doctor or a scientist, so let’s look at the Cleveland Clinic’s definition:
“Your body usually fuels your muscles with oxygen (aerobically). If you start doing intense physical activity faster than your body can get oxygen to your muscles and other tissues, your cells break down glucose to create the energy you need to keep moving (anaerobically). Lactic acid is created when you’re generating energy anaerobically.”
Basically your muscles produce lactic acid in order to get enough energy to maintain the intensity of whatever exercise you’re doing. But there’s a catch. You can’t produce lactate forever. You will eventually hit limits — hunched over, wheezing-your-brains-out, limits.
Why would I test my lactate threshold?
On top of me wanting to establish a fitness baseline I can look at as I age into oblivion, knowing my lactate threshold will give me exact heart rate zones to train in.
These zones are heart rate ranges that tell me how intense a given training session is. Intuitively, you likely already know that if your heart is pounding in your chest, you’re either in an intense training session, or you’re watching the opening scene in Finding Nemo for the first time when that Barracuda slaughters eats like a thousand eggs2.
Somewhere between that pounding-in-your-chest heart rate and complete rest there are optimal zones to train your body in. If you go too intense (in too high of a zone) all the time, you’re likely to get injured. If you go too light, you’re not giving your body the maximum chance to adapt and improve fitness. If you go just right, you’ll push your body just enough to make it adapt, without getting injured.
The Five Zones
Most people use 5 zones. I’ve heard of a 7 zone approach as well, but…. that seems excessive. At a high level, I think of the 5 zones like this:
Zone 1: Super easy, rolling around with kiddos on the floor
Zone 2: Easy, speaking in full sentences, no problem
Zone 3: Medium, running with someone who’s faster than you but you don’t want to hold them back
Zone 4: Intense, trying to get a 5k PR on Strava
Zone 5: Most intense, trying to exorcise the demons out of yourself
I’ve learned that most of my training should be in Zone 2. I used to get injured all the time. Shin splints. Runner’s knee. Hip tightness. Sore back. All of these were likely due, in part, to me running in either Zone 3 or 4 for all of my runs. This past year is really the first time when I’ve tried to focus on going that easy, Zone 2 pace. So far, nothing too crazy.
Now, most people, including some (almost) elite marathoners, have never done a lactate threshold test. Up until now, I’ve never had specific zones. I’ve just tried to go off of vibes (how my body feels). This has worked fine, but as a dad and husband, I’d like to optimize my training time. If I can make my training more effective, that means I can run faster. Running faster means getting home faster. Getting home faster means more magna-tile towers and lego houses. IYKYK.
In my next essay, I’ll break down the mechanics of the test itself, and share my testing results.
Should I get a lactate threshold test?
I know, the intro to this post made it sound super fun, right? Honestly, it was. One of the funnest runs I’ve had. Easily the funnest treadmill run, ever.
A large part (most?) of that fun was due to Dayna, the coach from PR Performance Lab. She’s awesome. Super sharp. Knows her stuff. She didn’t even judge me when I looped my 4 song playlist3 for half an hour straight. Strongly recommend looking her up if you’re in the Southern Utah area (not sponsored). If I ever get to the point where I am mentally ready to hire a coach, she’ll likely be the one I go with. Dayna has lots of helpful articles on her website, prperformancelab.com, such as how to fuel for a half marathon, strength exercises for runners, and which metrics you should focus on for running.
The other reason I enjoyed it was I just enjoyed pushing myself that hard. As an incredibly sub-par athlete my whole life, I’ve never really pushed myself to failure while running anything longer than 400 meters. Running that hard was an awesome mental experience. That day I was able to push myself mentally to the full limits of my body. Big confidence boost.
So should you get one? Yes, if you want to push yourself. Or if you want to get specific about your heart rate zones. Otherwise, you can get some of the way there by just going off of vibes, like I did for a few years. Your zone 2 training should be “can I keep a conversation with full sentences?” mindset.
Legal stuff
To close us out, I’ll offer the same warning that the Cleveland Clinic gives:
Never intentionally workout until you’re exhausted. Lactate threshold tests must be done under a provider’s supervision to make sure you’re safe. Talk to your provider if you’re interested in a lactate threshold test as part of your training or exercise.
Again, strongly recommend working with Dayna. She offers lots of different types of testing on top of lactate testing, including gait analysis and
— Stevo
See the Cleveland Clinic’s post on lactic acid: https://my.clevelandclinic.org/health/body/24521-lactic-acid
Seriously, who opens a movie like that?
At the risk of the internet’s judgement, here’s that playlist. Don’t judge the Grinch song until you’ve ran to it. It works. Tyler, the Creator saved Christmas. Why only four songs? It gets my mind into a meditative state. I’ve found music fades into the background if you know what’s coming. Four is enough to change it up just enough to not be too repetitive.