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The Talk Test vs. lactate and ventilatory thresholds

September 16th, 2011

Figuring out how hard to push is one of the great challenges in exercise. Personally, I’m a big fan of relying on perceptual methods (“how hard does this feel?”) rather than seemingly objective approaches like heart rate or lactate level. Certainly for competitive athletes, learning to interpret your body’s cues is a crucial step to being able to pace yourself properly in a race. But perceived exertion can be pretty tricky for beginners — which is why simple tricks like the “Talk Test” can be very helpful.

In its most basic form, the Talk Test is pretty simple: if you can talk in complete sentences, you’re below threshold. If you can’t talk, you’re above threshold. If you’re in the middle — you can say a few words at a time — you’re pretty close to threshold. So what is this “threshold” we’re talking about? Ah, that’s where it gets complicated. As exercise gets more intense, your body may or may not pass through several thresholds related to breathing rate, lactate accumulation in the blood, and other physiological parameters. The precise definition of these thresholds — and their very existence, in some cases — is hotly debated. As a crude simplification, threshold pace corresponds to the fastest pace you can sustain aerobically, which usually turns out to be the pace you’d hold in a race lasting about an hour.

All of this is by way of introduction to a new study from researchers at the University of New Hampshire, published in the Journal of Sports Sciences, that compared the exercise intensity at various points in the Talk Test to the exercise intensity at the ventilatory and lactate thresholds. Here’s the data, expressed in terms of heart rate and VO2:

“Negative Talk Test” is when the subjects couldn’t talk comfortably; “positive Talk Test” was when they could talk comfortably; “equivocal Talk Test” was in the middle. It’s clear that this middle zone corresponds pretty closely to lactate threshold. This is a bit surprising, since you’d expect ventilatory threshold — when breathing gets significantly harder — to be more closely tied to talking ability. But it’s convenient, because people care a lot more about lactate threshold than ventilatory threshold.

So how do we use this information? Here’s a basic “training zone pyramid” that I included in a Jockology column on pacing last year, based on research by Carl Foster and others about the typical training patterns of endurance athletes:

So most of your training should be below threshold — a common mistake beginners make, since they’re so unfit, is to be pushing above threshold on every bout of exercise. And some of your training should be at threshold — and I’d bet many competitive runners would badly fail the Talk Test during what they claim are “tempo runs” at threshold! On the other hand, casually spinning the wheels of an exercise bike while reading a magazine is unlikely to do much for you, as the press release from the UNH researchers points out:

“If you are beginning an exercise program and can still talk while you’re exercising, you’re doing OK,” Quinn says. “But if you really want to improve, you’ve got to push a little bit harder.”

 

  1. BMan
    September 16th, 2011 at 19:35 | #1

    The Talk Test and Swimming: You can do the talk test while swimming, believe it or not. For most strokes, oxygen is being restricted, so it makes it tough, even though you could just talk into the water. But you can certainly do it backstroke (though doing it in a long course pool is much better as you spend far more time underwater, oxgen-deprived, in a short course pool, leaving less time for an accurate test.

    However, as you get in better shape, or at least to elite endurance athlete, that Talk Test is not accurate. I don’t know if this applies to running and/or cycling (I’ve often wondered if the constant oxygen-deprivation is what causes this; perhaps some input from others would be nice), but when in really good swimming shape one can talk at a pretty high heart rate (as in, carry-on a conversation w/ a coach walking down the side of the pool while doing backstroke).

    Also note that it becomes extremely difficult to get to VT when in this condition.

    So my question would be, does this mean that oxygen is never the bottleneck in the burning of carbohydrates (or more accurately, the burning of the lactate that results from burning carbs)? If so, what would this imply for training needs?

  2. September 17th, 2011 at 02:30 | #2

    Thanks for posting this. I always wonder about the “talk test” while I jog. I am fairly new at the running thing, and despite trying to take it easy, I don’t think I could “comfortably talk” while jogging. I’d probably consider myself on the threshold for most runs, able to say a few words here and there, but not comfortable to carry on long sentences. But at what point should someone who’s new to exercise really worry about this? I mean let’s say I’m running a 13:00 or 14:00 minute mile, should I really be pulling it back to a 15:00 or 16:00? Isn’t there some level of beginner where this isn’t going to work for?

  3. alex
    September 17th, 2011 at 04:05 | #3

    @BMan: Thanks, that’s great — I never would have guessed that the Talk Test would apply in swimming.

    Re: “…does this mean that oxygen is never the bottleneck in the burning of carbohydrates…”: The question of exactly where the bottleneck lies is highly controversial. In general, getting oxygen into the lungs is NOT the problem — other limiting stages are the diffusion of oxygen from the lungs into the blood, circulation of the blood to the muscles, uptake of oxygen from the blood into the muscles, etc. Depending on how you set up the experiment and who you study, you can find evidence that any one of these factors is the bottleneck, so no one really agrees on whether there’s a single bottleneck. But again: heavy breathing is something we notice because it’s so disruptive, but for most people it’s not what’s holding them back. (And if it is — i.e. if they’re hyperventilating or something — it’s more likely due to panic at unfamiliar exercise intensity than an actual shortage of oxygen entering the lungs.)

  4. alex
    September 17th, 2011 at 04:15 | #4

    @FrauTech: Yeah, for a complete beginner I’d say the key test is: is this something you are willing to keep doing? If running a 14:00 mile puts you above the Talk Test, but you’re okay with that, then no problem — keep doing it, and it won’t take too long until your body starts to adapt, and you can (a) increase the pace, but also (b) perhaps dial down the relative intensity for some of your runs, especially as you start to make them longer. (Ultimately you want a mix of longer “easier” runs and shorter “harder” runs — not just the same thing all the time.)

    I think it’s a fairly common thing for people to start running, do their 14:00 mile and have it feel very hard and uncomfortable, but think “Well, this is so slow compared to the other people I see jogging in the park, I guess it’s supposed to feel that hard.” But the truth is — like the “training pyramid” I put in the blog post — I generally spend 70% of my time running at an effort that feels totally easy and where I’m not breathing hard at all. So if you’re struggling, don’t hesitate to ease off the pace, or alternate jogging and walking, to keep just below that Talk Test threshold most of the time. The most important thing is if you’re still doing it (and hopefully enjoying it) in six months.

    One other thing to note, from the journal article:

    “For example, irregular breathing patterns that are typical in beginning exercisers make non-invasive detection of the ventilatory threshold extremely difficult, if not impossible.”

    In other words, beginners tend to pant irregularly. They’re not familiar with the demands of aerobic exercise, so their body hasn’t quite figured out how to settle into an optimal, efficient breathing pattern to meet their oxygen needs. So this can disrupt the Talk Test a bit.

  5. Allen
    July 10th, 2012 at 20:04 | #5

    The talk test has me a little confused still. Am I aiming for the intensity at which I can string a full sentence together, or the intensity at which I can get a full sentence out with little effort? Some effort? There still seems to be a lot of room for interpretation. “Conversational pace” has me confused as well. Am I aiming to be able to just barely get out a sentence after which I can breath and recover while my partner is speaking or should I be able to speak multiple sentences. I remember reading that Carl Foster did his research using the Pledge of Allegiance, which is obviously a lot longer than a standard phrase or sentence. Again, speaking the Pledge comfortably could mean a lot of things. Are you aiming to get out all the words in one breath? Can you say it while taking in a breath or two? These are all questions that I’ve had about the talk test. When I run it seems there is a difference between the intensity at which I can get a full sentence out vs. the intensity that I can get a full sentence out and then repeat speaking right away. The whole thing has me a little confused. If you had any insight I would greatly appreciate it!

  6. not a beginner
    August 8th, 2012 at 05:41 | #6

    According to the attached pyramid, if you would like to run 10K in 60 minutes, you should run at the pace of 7:00 – 7:56 per kilometre below 80% of max. I’ve been running for several years and I’m still unable to run at that (relatively low) pace without my heart rate creeping over that 80%. And I’m unable to speak in full sentences too. So does that mean I’ve been running too fast all this time? I think I should by now be able to run at 7:30/km at relatively low heart rate. But I’m not. This bothers me quite a lot as it seems that I’m getting nowhere with my running.

  7. alex
    August 10th, 2012 at 10:37 | #7

    @not a beginner
    Thanks for the comment. It’s really difficult to know for sure whether you’re running too fast or slow based on limited information. But my general advice would be that SOME of your running should be done very hard (i.e. well above the Talk Test threshold), and some should be done more easily (able to speak).

    “Speaking in full sentences” might be a little too easy for some people — there’s quite a bit of variation. But on easy days, you should certainly be able to converse, even if it requires a bit of panting to get your words out. In terms of 80% max, are you sure you really know what your max heart rate is? The only way to know for sure is to do a progressive exercise test to failure — those age-based formulas are not reliable.

  1. September 21st, 2011 at 02:01 | #1
  2. September 21st, 2011 at 09:54 | #2