Back in November, I reviewed a series of videos from the online cycling magazine GCN. In that review I mentioned that the authors felt that heart rate was not a good way to identify one's Zone 2, but that breathing rate was. The criterion they suggested for the top of Zone 2 was the point where conversation is forced but possible. This metric is used, in various forms, by many coaches and is called the Talk Test. I do not find the criterion used by GCN easy to use because it is vague; what exactly does it mean for conversation to be forced but possible? Recently, I encountered an alternative version of the Talk Test which I found much easier to use, a version called the Counting Talk Test.
The Counting Talk Test (CTT) is a way of quantitating the Talk Test. In the Counting Talk Test, you exhale, take a deep breath, then count "One one thousand, two one thousand, three one thousand..." until you cannot count one number higher without taking a breath. This measurement is made while resting and then during exercise. The results of the Counting Talk Test is expressed as the percentage of number a patient can reach during exercise relative to what they can reach while resting. The table at the top of the post shows the results of my first attempt to use that test. What I did was get on my trainer, set the gears at 61", ride at 60 rpm for five minutes and then executed the CTT. I then increased the gear to 71" (maintaining my cadence at 60 RPM), rode for five more minutes and then repeated the CTT. I repeated this for 80". 91", and 106". At 106" I was only able to continue for 2 minutes. I then reduced the gear to 71" and measured CTT after 5 then 3 minutes. As I acquired more experience with the CTT, I have gotten better executing it. One consequence of this is that I have decided that my resting CTT is closer to 23 counts rather than the 16 counts measured in that first test, so I now calculate my percentages relative to that constant value of 23.
I encountered the Counting Talk Test in the Journal of Exercise Physiologyonline (JEPonline) Volume 5 Number 1 February 2002. This paper, and in fact every paper I have encountered that investigates the Counting Talk Test, considers it in a medical context rather than a sports context (which is why I used the word patient rather than athlete in the previous paragraph.) The medical community mostly uses a three zone Intensity system, Easy, Moderate and Vigorous, as opposed to the seven Intensity zone (Zones 1 through Zone 7) that the coach I follow, Coach John Hughes, uses. However, over the years I have come to the conclusion that the top of most coaches' Zone 2 and the top of the medical communities' Moderate exercise zone are both equal to each other and equal to the aerobic threshold. Since locating my aerobic threshold is probably the most important use I have for the Talk Test, the difference in training zone systems was not a big limitation. What was a big limitation is that the authors of this paper chose not to distinguish between Moderate and Vigorous exercise but considered the two together (they reported a value for the Counting Talk Test of 55% at the bottom of Moderate Exercise and 30% at the top of Vigorous Exercise.) The value I needed, the boundary between Moderate and Vigorous exercise, was not reported. A search for a scientific study that did report that value lead to Frontiers in Physiology Volume 13 article 832647 2022
The Frontiers in Physiology paper was, in fact, a comparison between the Counting Talk Test and an alternative they developed, the Regulated Monosyllabic Talk Test. I was not persuaded to switch to their Regulated Monosyllabic Talk Test but did find this paper useful because it reported the values for the Counting Talk Test at lower and upper boundaries of the Moderate (63% to 48%) and Vigorous (48% to 32%) exercise zones.
Both of these papers had as their goal the use of some version of the Talk Test to find the boundaries of the Moderate and/or Vigorous Exercise zones. To do that, they had to know where these boundaries are and then measure the value of their Talk Tests at these boundaries. How did they define these boundaries? Unfortunately, they did so using Heart Rate, exactly what GCN (and others) have argued should be avoided. In response to that concern, I compared the CTT to the version of the Talk Test used by GCN and determined that the percentages given in the Frontiers in Physiology appear to be about right, at least for me.
How does the CTT compare to heart rate as a way to measure Intensity? The main thing I use heart rate for is to measure average Intensity of a ride and thus cumulative Load over time and the CTT is impractical for that purpose. The reason I initially pursued it was that it was one more test that I could use to determine if I had correctly located my aerobic threshold. Having done that I now continue to use now and again it because it is free of some of the complexities of heart rate. Heart rate can be higher or lower based on fatigue, stress, caffeine, environmental temperature, etc. Based on my experience so far, CTT seems to be much less sensitive to such considerations. Also, heart rate is a lagging indicator, it takes time for it to increase after Intensity increases. As best I can tell, CTT responds to an increase in Intensity with little or no delay.
Does the aerobic threshold I measure using CTT agree with what I had previously assumed it was? The answer to that question is not so simple, as is illustrated by the following output from the software used by my heart rate monitor:
This ride was on my Trainer and done at a constant effort, 70 RPM in a 71 inch gear. The Counting Talk Test yielded a value of 11 counts which corresponds to 48%, the top of Zone 2. However, my average heart rate over the course of that ride is 123 beats per minute which corresponds to the middle of Zone 2. Is this a disagreement? Perhaps, but note that, although I held my Intensity constant over the 30 minute of the ride, my heart rate was not constant but increased during at least the first half of the ride. If I look at only the second half of the ride, my heart rate, estimated by the white line, is at 132 beats per minute, much closer to the top of Zone 2. I suspect that my heart rate during the first half of the ride is not a good indicator of Intensity because heart rate lags behind Intensity. If this explanation is correct, then the Counting Talk Test agrees with the other approaches I have used to locate my lactate threshold.
In summary, I think the Counting Talk Test is a better way to estimate breathing rate than the approaches suggested by the exercise community to date. To be most useful, the exercise community would have to adopt the CTT (or something similar) and calibrate it against reliable laboratory measures of Intensity like blood glucose or O2/CO2 levels in the breath. This would provide a clear, accurate way for the average athlete to locate their aerobic threshold quickly, easily, and inexpensively.
