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Table of Contents

• Running on Empty? Let's Talk Lactate Thresholds an …

• David Bonham-Pole Vaulter shares a lot in common w …

• Episode takeaways:

  • References used for the MMB

Running on Empty? Let's Talk Lactate Thresholds and How to Measure Them

This episode features a Medical Mailbag segment that tackles the topic of lactate sensors. Are they the key to unlocking athletic potential, or just another gimmick? Jeff and Juliet dive into the science, weighing the pros and cons of these gadgets. With a bit of sarcasm, they dissect whether these sensors are genuinely beneficial for everyday athletes or if they’re just another trend we’ll all forget about by next year. These gadgets that promise to unlock the mysteries of your body and help you train like a pro. But let’s be real—do they actually work, or are they just another shiny toy to throw your money at? There is no doubt that science has shown that lactate threshold is real, these devices can be used to measure that and using that information can inform your training and racing. The real question is whether this makes them worthwhile or can you continue to use the indirect measures that most are using already.

David Bonham-Pole Vaulter shares a lot in common with the older AG triathlete

David on David: I live in the Denver area with my wife of 31 years. We grew up together in Ohio and have been together since middle school. I am 54 years old and have a daughter in her first year of college. I have worked in the field of Conservation law enforcement for 33 years. My family and I have a hobby farm with horses and other livestock. I am the volunteer Pole Vault Coach at the Conifer High School.

We’re introduced to the world of masters pole vaulting through the story of David Bonham—a man who, after years away from the sport, finds himself back in the game thanks to a little nudge from his daughter. Now, don’t get me wrong, this isn’t just a tale of jumping over a bar; it’s a saga filled with heart attacks, knee injuries, and a whole lot more. David’s narrative starts with him reluctantly donning the coach’s hat, only to realize that the thrill of vaulting is too intoxicating to resist. He humorously reflects on the absurdity of being the oldest participant at practice, laughing at the generational gap while simultaneously facing the physical realities that come with age. As we dive deeper into David’s story, we learn about the heart attack that changed his life. Instead of retreating into a sedentary life, he uses this traumatic experience as fuel for transformation, shedding pounds and rediscovering his love for pole vaulting. His journey isn’t just about personal victories; it’s a heartwarming reminder of the importance of support systems—his wife and daughter play a pivotal role in encouraging him through thick and thin. David’s candidness about the challenges of returning to the sport after a significant injury is both refreshing and relatable, as he shares the ups and downs that come with recovery. You’ll find yourself nodding along as he recounts the joys of training and the pains of aging.

Episode takeaways:

• Lactate sensors can provide insight into training zones, but their effectiveness and utility varies.

• David's journey from heart attack survivor to pole vaulting master showcases resilience and passion.

• Age should never be a barrier; pursuing what you love can be incredibly rewarding.

• Recovery from injuries takes time, and it's important to listen to your body during the process.

• Creating a supportive environment, like David's family, can make all the difference in athletic pursuits.

• The balance of training and recovery becomes crucial as age increases, influencing performance.

References used for the MMB

1. Paper that tests the accuracy of lactate sensors, AND gives an overview on how blood lactate is measured:

Mentzoni, F., Skaugen, M., Eythorsdottir, I., Roterud, S., Johansen, E. S., & Losnegard, T. (2024). Precision and accuracy of four handheld blood lactate analyzers across low to high exercise intensities. European journal of applied physiology, 124(12), 3781–3788. https://doi.org/10.1007/s00421-024-05572-6

This paper looked at the effect of lactate sensor on the accuracy of measurement for the blood lactate of one 35 year-old cyclist riding at 4 different RPEs. They determined accuracy by using the Biosen stationary sensor as a benchmark, and re-tested the analysis using the other stationary sensor. The handheld sensors they tested were: Lactate Plus (Nova Biomedical, USA), Lactate Pro2 (Arkray KDK, Japan), Lactate Scout 4 (SensLab GmbH, Germany), and TaiDoc TD-4289 (Taidoc Technology Corporation, Taiwan). 

The authors found that stationary analyzers were more accurate than handheld lactate analyzers. The handheld lactate sensors were variable in their accuracy: The mean relative differences to Biosen were 7% (Plus), 7% (Pro), 10% (Scout), 42% (Tai), and 32% (Ysi). Sensors were more accurate when blood lactate was higher (sensors were not able to differentiate low blood lactate levels accurately). The precision of these sensors were estimated to be off by between 0.2mM - 0.4 mM.

• AND how is blood lactate measured? 

  • Lactate molecules are converted in an enzymatic reaction, normally using lactate oxidase to turn lactate into pyruvate and hydrogen peroxide. Hydrogen peroxide is oxidized, which releases electrons, and a lactate testing device will measure the magnitude of that electrical current. 

2. Another paper that specifically review lactate sensors: 

Bonaventura, J. M., Sharpe, K., Knight, E., Fuller, K. L., Tanner, R. K., & Gore, C. J. (2015). Reliability and accuracy of six hand-held blood lactate analysers. Journal of sports science & medicine, 14(1), 203–214.

This paper looked at the effect of lactate sensor on the accuracy of measurement for the blood lactate of 6 participants measured at 5 different ranges of blood lactate, ranging from low to high. They determined accuracy by using stationary/laboratory samplers, one of which does not use the electrical current measurement method. The handheld sensors they tested were: Lactate Pro, Lactate Pro2, Lactate Scout+, StatStrip® Xpress™ Meter and The Edge. All used the electrical current technology described in (4), but the Xpress sensor additionally corrects for interfering substances such as haematocrit, acetaminophen, uric acid and ascorbic acid.

 The authors found that analyzers varied in their predictability and reliability such that different sensors would be more or less useful in different situations. Sensors better at predicting lower ranges of lactate would perhaps be more useful to clinicians than athletes, and processing time of a sample may or may not be an important factor in choosing a sensor. The authors also said that “biological variation… swamps analytical variation,” meaning that these sensors can be used to compare values derived from one individual, even over time. The sensor need only be from the same manufacturer. The authors note that the Edge and Lactate Pro2 were the most reliable sensors at high lactate concentrations (the likely useful range for athletes wishing to test their lactate in training).

3. Why lactate threshold training can be helpful:

Sjödin, B., Jacobs, I. & Svedenhag, J. Changes in onset of blood lactate accumulation (OBLA) and muscle enzymes after training at OBLA. Europ. J. Appl. Physiol. 49, 45–57 (1982). https://doi.org/10.1007/BF00428962

This study looked at the effect of an additional weekly 20-minute run at lactate threshold in 8 men who were already training as middle- or long-distance runners. OBLA increased, and the authors also observed an increase in LDH-1 and a decrease in both PFK activity and PFK/CS ratio that led the authors to conclude that training at lactate threshold increases lactate threshold, and that this increase in lactate threshold does not accompany a change in maximal aerobic power due to likely adaptation of skeletal muscle.

4. A review paper that challenges whether lactate measurements are able to be measured accurately at all, and if they are, whether they’re meaningful… the authors are skeptical.

Swart J, Jennings C (2004) Use of blood lactate concentration as a marker of training status. South Afr J Sports Med 16(3):1–5.

Inaccuracy of sensors, carbohydrate depletion, mode of exercise, ambient temperature    and muscle damage or overtraining (warm temps increase muscle glycogenolysis and can increase lactate concentrations)

5. The “Norwegian method” - this paper looks at lactate testing through the lens of the success of Norwegian middle-distance runner Jakob Ingebrigtsen, primarily taking a historical lens to summarize trends in elite running training over time and their scientific support.

Casado A, Foster C, Bakken M et al (2023) Does Lactate-guided threshold interval training within a high-volume low-intensity approach represent the “next step’’ in the evolution of distance running training? Int J Environ Res Public Health 20(5):3782.

6. The effects of training on lactate threshold vary with age:

Denis, C., Dormois, D., & Lacour, J. R. (1984). Endurance training, VO2 max, and OBLA: a longitudinal study of two different age groups. International journal of sports medicine, 5(4), 167–173. https://doi.org/10.1055/s-2008-1025899

This study looked at the effects of cycling as training on young vs. middle-aged men. VO2max increased as a function of training moreso in the young subject group than in the middle-aged subject group. Absolute OBLA and OBLA relative to VO2max were found to increase in both groups, but relative OBLA increased only for the young subject group.

 Many metrics did increase and benefit were similar to younger and older but this one metric showed a difference

7. Ear sampling is more precise than finger sampling: 

Zhong, F., Chen, Z., Gu, Z., Wang, X., Holmberg, H. C., & Li, Y. (2025). Comparison of lactate measurements from earlobe and fingertip capillary blood using Biosen S-Line and lactate scout analyzers. European journal of applied physiology, 125(1), 145–156. https://doi.org/10.1007/s00421-024-05585-1

This study looked at the effect of finger vs. ear sampling of lactate threshold on 40 healthy participants. They found an increase in measured lactate at the fingertip compared to the earlobe, and that the earlobe was a better measure of LS4.

8. Evidence that being “untrained” leads to more variability in measurements obtained at lactate threshold.

Heitkamp, H. C., Holdt, M., & Scheib, K. (1991). The reproducibility of the 4 mmol/l lactate threshold in trained and untrained women. International journal of sports medicine, 12(4), 363–368. https://doi.org/10.1055/s-2007-1024695

This study looked at the effect of training status on lactate threshold variability over two training sessions in a group of untrained (n=27) and trained (n=10) women. The authors found that for  oxygen uptake, speed, and heart rate (measured at threshold), the untrained group had more variability.

9. How to measure OBLA: Instead of LT4, try Dmax for better repeatability and predictive value (but Dmax requires measured power output).

Heuberger, J. A. A. C., Gal, P., Stuurman, F. E., de Muinck Keizer, W. A. S., Mejia Miranda, Y., & Cohen, A. F. (2018). Repeatability and predictive value of lactate threshold concepts in endurance sports. PloS one, 13(11), e0206846. https://doi.org/10.1371/journal.pone.0206846

Dmax method definition: “The new method consists of calculating the point that yields the maximal distance from a curve representing ventilatory and metabolic variables as a function of oxygen uptake (V̇O2) to the line formed by the two end points of the curve (Dmax method).”

10. An interesting paper on the historical development of our understanding of lactate threshold testing and its relevance in exercise

Myers, J., & Ashley, E. (1997). Dangerous curves. A perspective on exercise, lactate, and the anaerobic threshold. Chest, 111(3), 787–795. https://doi.org/10.1378/chest.111.3.787

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