Lactate Threshold: Life Begins Outside Your Comfort Zone

Posted: March 29, 2013 in Gym, Run
Tags: , , ,

My earliest association with anything called a “stress test” came in my teens while watching one of my all-time favorite cheese ball movies from the 80’s about professional cycling, ‘American Flyers’.  In hindsight, it was pretty lame, but it did have lots of cycling in it, a kick ass soundtrack (or, at least I thought so back then), Rae Dawn Chong, and a young Kevin Costner rocking a pretty bad ass cooler-than-Jesus mustache.  The movie revolved around sports physician Marcus as he persuades his unstable brother David to come with him and train for a bicycle race across the Rocky Mountains, the infamous ‘Hell of the West’.  What he doesn’t tell him, of course, is that he has a cerebral tumor (queue the dramatic organ HERE).  Whatever it was, this flick features great views of the Rockies and served as my first insights into the basic tactics used in bicycle racing.  Now, I don’t want to spoil the movie for you or anything but, David wins, Marcus dies, Rae Dawn is hot, and the whole cycling thing was awesome.  Hey, throw in a bag of Cheetos and back then that was my ideal recipe for a perfect Saturday night.  Yes, things have certainly changed somewhat since then even though I still think Rae Dawn is hot.  Sue me.

However, in the movie, there is a pivotal scene where David undergoes the dreaded “Torture Test” where he’s hooked up to all sorts of electrodes and literally has his bollocks run off on a treadmill in his quest to beat his brother’s record of 25 minutes and 14 seconds.  Total cinematic gold if you ask me.

Now, even though I now know that this kind of test is better known in the real world as a ‘VO2-Max’ test, when I first accepted the offer to undergo a ‘Lactate Threshold’ test at the local Niagara College, I still kinda expected it to be something similar to this; electrodes, sweat, gasping, cheering, and total maximum awesome.

Of course, it was probably more like this (minus the mask):

But, anyway, I digress.  So what is this whole ‘lactate threshold’ testing and why would I ever want to subject myself to something like that anyway?  Well, as it turns out, it has nothing to do with lactating, breast feeding, or even breasts at all.  Imagine my disappointment (queue the sad trombone HERE).

Basically, the lactate threshold test is a means by which to measure your aerobic endurance; revealing how powerfully and how long you can race. In a nutshell, using the results can help with prescribing exercise intensities, monitor training adaptations, and enhance your overall performance in the long run.  Pretty nifty, right?  This is all well and good, of course, but what is this magical ‘lactate’ exactly?

To produce energy for movement, the muscles primarily use fat and carbohydrate for fuel.  When carbohydrate – the sugar-based fuel source – breaks down, lactic acid is produced in the muscles as an after effect.  As this lactic acid seeps out of the muscle cell and into the blood and surrounding body fluids, hydrogen ions are released, and the resulting salt is called ‘lactate’.  Yeah, not quite so enticing is it?  The amount of hydrogen ions and lactate increases as the intensity of the exercise increases.  At low levels of production, the body efficiently removes and recycles them.  As your exercise increases in either intensity or duration, the removal of this lactate waste isn’t quite so efficient, and the build-up of hydrogen ions begins to interfere with energy production and muscular contractions necessary for movement, thus causing fatigue and discomfort; and that’s putting it mildly.  This production of lactate, or lack-thereof in this case, is how Lance Armstrong used to explain his freakish performance in the Tour d’ France before we all learned that it wasn’t lactate (or lack of) coursing through his veins, but EPO instead.  But I digress.  So measuring the lactate in your blood as you shift from aerobic (light breathing) to anaerobic (labored breathing) exercise, or the level of intensity at which you begin to accumulate this waste, will help determine your ideal “threshold” at which you can sustain an effective pace.  Capeesh?

Think of it this way; imagine slowly pouring water into a paper cup that has a hole in the bottom allowing the water to run out as fast as it goes in.  This is what happens to lactate in the blood during low levels of exertion.  By pouring faster, there comes a rate at which the water goes in faster than it comes out, and so the cup begins to fill.  This is similar to what happens with lactate in your bloodstream during exercise of increasing intensity.   The point at which the water first begins to accumulate is analogous to the ‘Lactate Threshold’.  So, exercising, or racing, at a slow rate of exertion (aerobic), you could probably go on for hours but I wouldn’t expect to see many spectators left at the finish line to see you finish.  The harder you push yourself at a greater intensity (anaerobic), or faster you try to make yourself go, the lesser amount of time you can actually sustain that pace.

So when the opportunity was announced through my TryForce group that this type of testing was available to members, I jumped on the chance as the tests were going to be conducted by Natalie, the same ‘Exercise Science for Health and Performance’  grad student who devised my functional strength program a few months ago that I still use today.  So why not see what other means she has to kick my ass, right?  Besides, with these results, I would have a good viable starting point at where, or at what intensity (measured by heart rate), I should be conducting all my long and slow, tempo and speed workouts in order to maximize the overall results of my training.  So it was all set; time to get my hurt on.  Suuuu-weet!

I’ve never been part of a formal lab test before aside from those, well, questionable ones back in university where I was dosed to the gills on a Friday night and left to watch movies for a few hours while technicians with clipboards observed me through a Plexiglas window; much less anything fitness based.  So I was not sure what to expect.  A few instructions were sent out via email a few days prior:

  • Wear loose clothing
  • No exercise 6 hours prior
  • No alcohol 2 hour prior
  • No smoking 2 hours prior
  • No food 2 hours prior
  • No caffeine 2 hours prior

These instructions were all simple enough and easy to follow, even though it meant that I’d had to give up my vodka martinis for breakfast apparently.  The last two though, no food or caffeine for two hours was going to be a bit difficult since I eat, like, constantly, given the amount of calories I typically burn in a day with all the swimming, biking, running and whatnot.  As a result, I was still shoveling in scrambled eggs, toast and orange wedges right up the last very allowable minute.  You’d think I was going on a month long fast in the desert right afterwards or something from the way I was frantically spooning in the last of my breakfast.  At one point I nearly choked on the last dregs of my coffee and barely made it to the sink before the remnants sprayed out my nose.  Yeah, I’m classy like that.

When I first arrived in the lab there were already a few sweaty, exhausted friends still givn’er on the treadmill, so that much of the equation was holding true.  It was then explained to me that I could similarly conduct the test on a treadmill, or on a spin bike if I preferred.  This, apparently, is the classic ‘pistols at dawn’ type of choice for testing triathletes.  I also noticed that there was a complete lack of electrodes, high-end technological gadgetry, or fancy electrical gizmos of any kind.    Not necessarily a big deal, of course, but part will definitely admit that there is a certain cool factor (and bragging right) to being hooked up to this kind of shit and a bit of me was disappointed.  Oh well.

Does this look like fun or what?

Does this look like fun or what?

What was prevalent was an entire table of gauze and menacing looking stabby things.  That can’t be good.  Then it registered, ‘how else are they going to test the lactate in your blood?’  Of course, they would have to extract it one way or another.

I decided that since I’ve already done quite a bit of threshold work on the bike during my Thursday night spin classes, I would revert my suffering to the treadmill as I am about to launch myself into more full on run training and knowing my particular running thresholds will serve me great purpose in the coming months for sure in my bid to acquire some of this here elusive ‘speed’ I keep hearing people talk about.  Before I could jump on the treadmill however, I needed to have some preliminary physiological measurements taken such as my age, height, weight, and blood pressure.

Funny thing about having my blood pressure taken – I hate it.  I have no reservation about running on a treadmill for rapidly increasing intervals until I’m ready to puke, but the feeling of actually feeling my heart thumbing in my upper arm as that cuff begins to constrict itself makes me, well, queasy.  So much so, that my blood pressure was first recorded at 169/96 mmHg.  Logistically, they needed a reading of 145/100 mmHg  to proceed with the test safely.   So who suffers from ‘white coat syndrome’ apparently?  This guy!  Crap! How embarrassing would that be if I couldn’t even past the preliminary blood pressure reading to proceed to the actual LT test?  Just.  Shoot.  Me.  Now.  Thankfully the next reading came in at 144/92 mmHg, falling just beneath the required standard so I began to ready myself for the next phase of getting down to business…the drawing of blood.  Oh joy.

What greeted at this next stage of the process, it was kinda on par with something you might expect to see on Vlad Tepes bedside table: gauze, a dozen needles, and alcohol swabs.  Goodie.  Hey, are we doing a Lactate Threshold test here or conducting some weird medieval bloodletting ritual or something?  It’s hard to get motivated while facing at such a macabre set-up, but it’s simply a part of the test since they need to measure the amount lactate in your blood through the various intervals to determine any fruitful results.  Fortunately, my student observer was a sweet, kindly looking girl despite the intimidating lab coat.  “Okay, ready to start?” she asked.  “It’s going to be a piece of cake, believe me.  It’s not so bad.”   Sounds simple enough, right?

Well, what I really heard was:

Apparently, as is evidenced by the plethora of shaving cuts on my face, I am an easy “bleeder” and it only took the girl one stab to draw blood establish the benchmark by which to begin my test.  Queue the agony.

Basically, the entire test is conducted on a graduated system of intervals that steadily increase in intensity from an initial easy pace.   Using what’s known as a “Borg Scale”, a method of measuring my RPE (Rate of Perceived Exertion), which ranges from 6, being extremely easy to 20 being ‘I think a vein in my forehead is about to burst’, I would have my blood tested every 4 minutes as my intervals increased in intensity upward up that scale.  The Borg Scale looks exactly like this:

Brilliant thing this Borg Scale; I think we should incorporate something like this in all aspects of life.

Q: “How’s your day going?”

A: “Oh, I’d say about an 11 on the Borg Scale.”

Q: “This dinner is delicious!  Is the recipe difficult?”

A: “Not at all.  It’s only an 8 on the Borg Scale.”

Q:  “Hey, what took you so long in there?”

A:  “Are you kidding?  I just passed a turd that was at least a 19 on the Borg Scale.”

So, with my perforated fingertip dripping fresh blood and a Borg Scale placed squarely in front of me, I started to run at what felt like a fairly easy pace, or an 8 on the scale.  After four minutes, my blood was tested again and the interval slightly increased, this time to an 11, which, in Spinal Tap terms is pretty awesome – true – but for me this was still a pretty easy pace.  And so on and so forth through five more intervals over the next 30 minutes or so until my legs were turning over quicker than a hamster in a wheel, lungs gasping, head woozy, my heart rate racing to 173 bpm – thump thump thump thump – and climbing still.

The top was cropped out to spare you the literal mess that is my current condition, not to mention what little dignity I still have left.

The top was cropped out to spare you the literal mess that is my current condition, not to mention what little dignity I still have left.

The even less than less then fun part.

The even less than less then fun part.

Okay, so this is what prolonged death feels like.  Good to know.

So what were the overall results of this madness you ask?  Well, from the gathered information, they were able to determine that I’m fat and slow; big surprise, right?  And it only took $30 and an hour in the lab to determine that.  Yay me.  Basically, I can sum up the overall results in a cool looking graph like this:

LT4

After all, who doesn’t loves themselves an awesome, groovy graph?  Totally looks legit and official, right?  With this graph, they were able to determine a few other things of relative importance that will aid me in my training going forward, specifically, my first and second lactate threshold ‘spikes’.  Hey, if the graph says so then it must be – “All hail mighty graph!”  The first spike on the graph signifies the first slight increase of blood lactate in the curve, and second spike of blood lactate where my lactic acid is building up faster than I could clear it out.  From this data, they could determine my approximate heart rate zones for my different workouts, represented in this handy-dandy chart:

chart

Recovery:  This zone is primarily used during recovery from other faster intervals, or at the end of my training sessions (this value is <LT1).  I’ll also use this zone for all my easy runs.

Over-distance:  This is my long-slow-distance (LSD) day.  This value is the first half of the values between LT1 and LT2.

Endurance:  This is a slightly higher intensity version on the LSD day.  When I choose to do my weekly endurance intervals, I can work within these over-distance and endurance heart rate ranges.  This value is the second half of the values between LT1 and LT2.

Tempo/LT (lactate threshold):  When doing my high intensity training, I can use the lactate threshold to give me the appropriate heart rate ranges that I should be working within.  For example: if my heart rate range is 163-173 bpm  (my lactate threshold being mid-way through that range – or about 168 bpm), my high intensity intervals should be at the upper end of those values (168-173), and my recovery from these intervals will be at the lower end of the heart rate range (163-168).  By working slightly above this lactate threshold, I will be stressing my system and allowing for new adaptations to occur in order to improve my lactate threshold appropriately through effective training. This value is my LT2 +/- 5 bpm.

VO2:  This value/heart rate is working above my threshold. This is ideal for sprinting and working towards my maximum heart rate.  Obviously, this value is way above my LT/Tempo range where I can expect my chest to feel like one of those marines in Aliens just before an alien bursts out of it.

Now what do I do with all this?  Well, where my swim and bike conditioning has already been happening in earnest, my ‘official’ run training starts now.  I have spent the last three months building up my running base again from all those nagging foot issues I’ve been experiencing since Ironman, not to mention the multiple motivation issues, and, yes, the fat issues, and it’s once again time to up the ante a bit and get back to bid’ness of getting out of my comfort zone more often and once again tasting life and feeling the burn.

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