In June of 1970 I started graduate school at the University of Texas (UT). Seeking relief from the heat, I often ran on the UT track at night. There I encountered another runner, Jerry Lane. As runners do, we fell into conversation—about running, about how to train for running, and even made plans for our first marathon the coming fall. One of us, citing that prestigious journal Runners World, mentioned the idea that “if you can just about talk, then you’re training just about right.” I’m simple minded, so this idea stuck in my head.

I spent the next 6 years, guided by the texts of P.O. Astrand and K. Rohdal and B. Pernow and B. Saltin, got my degree, and over the ensuing years did lot of different research about VO₂max, running economy, muscle fiber type, sport nutrition, winter sports, exercise testing, cardiac rehabilitation, left ventricular function, cross training, RPE, pacing, and training monitoring. I was busy. I had a good career, judged by teaching students, doing a variety of research, and serving professional societies, all following those late-night runs. In 1998, I moved to University of Wisconsin–La Crosse, joining John Porcari for the last half of my career. There, debating student thesis topics, we found some older¹ and some newer² work on the Talk Test, the very thing that Jerry and I had discussed 30 years earlier. We reasoned that the Talk Test should be related to the ventilatory threshold (which was now easy to measure) and might provide a simple index of exercise intensity to guide training. We reasoned that, given the interest in RPE,^3,4 that the Talk Test might be useful in terms of regulating training intensity, but with the advantage of not requiring maximal exercise testing.

It proved to be a fruitful line of research. In just our lab alone, together with an informal international team of co-authors (Porcari, Bok, Boullosa, Barroso, Casado, Cortis, Festino, Fusco, de Koning, Rodriguez-Marroyo), we published ∼30 full papers and 2 reviews about the Talk Test.^5,6 It was also well studied in a number of other labs.^7–9 All of this began on a late-night run, with a complete stranger as a chance “running buddy” and inadvertent science partner, and with the impetus of, not prestigious journals like IJSPP, MSSE, JAP, JSCR, or EJAP, but Runners World. Yet again, the shape of part of my career was crafted, by serendipity.¹⁰

Simply, we learned that we needed a standard speech provoker in order to scientifically study the Talk Test, ∼40 to 100 words, recitable from memory or cue card. We learned that stages of 2 to 3 minutes work well. We learned that all you had to do was have the subject recite the paragraph, then ask “Can you speak comfortably?” Possible answers are “yes” (Positive)(POS)(below ventilatory threshold), “yes, but” (Equivocal)(EQ)(near ventilatory threshold), or “no” (Negative)(NEG)(near respiratory compensation threshold). An additional stage was the Last Positive-1, or the stage before the Last Positive.^5,6 The Talk Test translates from English to Dutch, to Spanish, to Danish, to Italian pretty well. The Olympic Oath (∼40 words) is our best candidate as a standard paragraph. Mechanistically, it works because the reduced breathing frequency during speech, occurring at points (ventilatory threshold, respiratory compensation threshold) where breathing frequency should normally increase, reduces VCO₂ and drives up the p_aCO₂ and end-tidal pCO₂, which makes speech less comfortable.¹¹

Unlike incremental exercise, during prolonged exercise of 20 to 60 minutes, depending on the cohort (patients to athletes), there is a tendency for the response to “drift.” The drift is bigger with progressive stages of the Talk Test but is remarkably constant across cohorts. Incremental stages such as the Last Positive-1 (LP-1) and Last Positive (LP) have little drift, the EQ stage drifts steadily, and the NEG stage drifts rapidly, such that it represents not normal training but nearly10-km competitive running intensity in athletes. There is good reliability of the exercise intensity associated with various markers of the Talk Test.

The point of this editorial is that we often ask similar questions throughout our academic careers. Physiologist Steven Horvath once opined that we are often asking the same question over and over again, but about every 25 years we have developed better technology to provide the answer. Viewed from a career-length perspective, the answers to these sequential questions evolve. The evolution often occurs in unanticipated ways. Normally, one might expect the answers to be more complete, more complex, more detailed, and more specific. Occasionally, however, the answer evolves to be exquisitely simple. Back in 1937, Oxford Professor John Grayson had proposed to Scottish mountain climbers that they should “climb no faster than they could talk,” suggesting a way to regulate exercise intensity during climbs that often took all day, or sometimes multiple days. This lead Toronto Professor Robert Goode to the “breath check test,” and us to the Talk Test, a situation where we find ourselves saying, “Is it really this simple?” At least for me, in this specific case, the answer is “yes.”