- The TriDoc Podcast-in Supplement form
- Posts
- Episode 182: Tymewear/Matthew Marquardt comes back
Episode 182: Tymewear/Matthew Marquardt comes back
A brief synopsis of the episode's main discussions and takeaways as well as extended references
Jeff Sankoff
October 24, 2025
It was interesting to take a deep dive on some tech that got a lot of buzz during the 2025 Tour de France and find that for once, there is actually something to the hype! Still, it’s not clear that this is something that every age group athlete is going to want to get or really needs to have. And of course, I was ecstatic for another chance to chat with my not so secret favorite pro triathlete, Matthew Marquardt
Table of Contents
Tymewear’s ventilatory mechanics measuring chest strap delivers on its promise but is it the game changer they advertise?
Every endurance athlete is intimately familiar with heart rate training zones and how that helps to inform their day to day training session intensity. Until recently, other than relying on perceived exertion, heart rate was really the only way we had of measuring physiologic training load in a non-invasive way (lactate measurements are another means but this requires repeated blood testing and is obviously invasive!). This past summer during the Tour de France there was a lot of excitement around the news that the Belgian super team, Visma/Lease-A-Bike was utilizing a new type of tech to get physiologic data in a new way. A company called Tymewear had developed a chest strap that provided a lot of the usual metrics like heart rate, vertical oscillation for running and ground contact time but had added respiratory metrics like tidal volume, respiratory rate and minute ventilation and was promising to revolutionize endurance training by offering a shift from heart rate measures to respiratory ones.
The issue here is that in some circumstances, heart rate may become unreliable but respiratory thresholds remain fairly constant and accurate across different conditions. The theory then is that by using respiratory rather than heart rate thresholds, you can have a more accurate determination of training zones and better direct training efforts and get a better overall response.
As always though, the devil is in the details. When we evaluated the research we found a few important things: 1) The Tymewear strap does what it claims to do and is accurate in measuring ventilatory metrics to provide ventilatory thresholds 2) Ventilatory threshold training is a more accurate means of determining training zone for some people and 3) using ventilatory threshold zones may be a more accurate means of training and may allow for more rapid training gains at least initially for the untrained individual.
As you can see there are still some uncertainties here such as; is this tech really that much better in trained athletes? Are the advantages uniform and sustained? Does this compare well for the most elite athletes? Clearly there is a sneaking suspicion that it does as the UCI is considering banning the technology in cycling but I am uncertain as to why as the science is not that compelling. Still, of all the technology that we have reviewed, this is one of those devices that we can definitely say, there is support for its claims and it does do what its makers say it does. Like the Calibre, another device that we had a similar take on, it remains to be seen if there are adequate real use scenarios to make this something that age group athletes should consider adopting at this time.
Matthew Marquardt-Medical student, professional Ironman triathlete and general all around amazing person
Matthew according to Matthew: Medical student at Ohio State University, 2x Ironman Champion, (Cairns & Lake Placid) IM Lake Placid Record Holder, 8th at Ironman World Champs, (top American) Future Head and Neck Cancer Surgeon
In this jam-packed episode of the Tridoc Podcast, we witness the whirlwind journey of Matthew Marquardt, a med student who’s also a triathlon sensation. With a season filled with victories, including a dazzling performance at the World Championships, Matthew shares the gritty reality behind the glamour of triathlon fame. From the grueling training schedules to the unexpected cramping that could rival any medical mystery, he takes us behind the scenes of his life as he balances studies and races. The conversation turns to the dramatic events at Kona, where high stakes and even higher temperatures led to heartbreaking moments for some of the sport’s best women. Matthew reflects on the emotional rollercoaster that these athletes endured and what it truly means to compete at such a high level under extreme conditions. The dynamic between the race’s history in Kona versus Nice is also a hot topic, highlighting the different styles of racing that favor various types of athletes. Matthew shares his thoughts on the loss of the World Championship rotating to venues other than the big island, his future as a professional at least in 2026 and how he manages to keep it all together with such a busy life and still be so genuinely happy about it all.
Episode takeaways:
Training with ventilatory thresholds may offer improved accuracy to some people, particularly those with specific heart issues or on some medications but whether or not it truly is for all athletes remains to be seen
Matthew Marquardt, a full-time medical student and triathlete, shares how he balances intense training with his studies.
The podcast discusses the importance of understanding body signals in extreme sports to prevent overexertion and health risks.
References used for the MMB
Tymewear Training System
Product website
Key Points:
The tymewear VitalPro is a water-resistant device that straps around your chest.
The device tracks the body’s response to workouts by measuring breathing and heart rates to detect metabolic thresholds and offers personalized training recommendations based on the data to its members
VitlaPro straps are sold for $299, and the Training Membership is another $150
Straps are available in two adjustable sizes
Devices are connected to the Tymewear app via Bluetooth
Users will take a 20-30 minute threshold test to identify personal thresholds
A metabolic profile is generated to create personalized training suggestions
The users can track workout metrics in real-time to help execute targeted training
Tymewear’s approach of using unique physiology data to personalize training zones differs from other training devices that are based on population averages
The analysis is best tuned for running, cycling, and cross-country skiing
The device measures the following breathing and performance metrics:
Tidal Volume (air volume per breath)
Breathing Rate (breaths per minute)
Minute Ventilation (air volume per minute)
Heart Rate
Player Load
Ground Contact Time
Air Time
Cadence
Elevation Changes
Personal thresholds for Zones 2-5: VT1, Balance Point, VT2, and VO2max
VT --- ventilatory threshold
The website links a Wolpern et al. (2015) study to claim that individualized training improves performance 2.4x faster
The website also notes 10+ years of research and includes a validation study that shows +/- 1 br/min breathing rate accuracy and 97% minute ventilation accuracy
Validation of the Tymewear VitalPro Chest Strap Against the Cosmed K5 Metabolic Cart for Ventilation Monitoring
Key Points:
This is a validation study reported on the TymeWear website, but it does not say who conducted the study or when
The study compared the VitalPro wearable chest strap to the gold-standard tool for continuous gathering of respiratory metrics and showed that Tymewear VitalPro provides an accurate and reliable respiratory monitoring
The breathing rate (BR) data had a mean absolute error of 1.2 breaths per minute, and the minute ventilation (VE) showed a strong pooled correlation (r=0.973, r^2=0.9476)
Methods: Participants were healthy male and female athletes (N=26; age 27+/- 21 years). Participants wore Tymewear Vital Pro chest strap and Cosmed K5 portable metabolic cart and performed a ramped VO2max cycling test (3 min/stage with power increasing by 20W). Metrics were processed the same way. Data compared using Pearson correlation and mean absolute error. Fisher’s z transformation was used to pool correlation coefficients across datasets.
Results: Mean Absolute Error: 1.2 breaths/min. Pooled Pearson Correlation (r): 0.973 (r² = 0.947). Strong linear association between data generated by VitalPro and Cosmed K5VE devices. Dataset lengths differed due to the use of different processing algorithms that detect different breaths.
Is a threshold-based model a superior method to the relative percent concept for establishing individual exercise intensity? a randomized controlled trial
Wolpern et al. 2015
Key Points:
This is the one published study that is linked on the Tymewear product website
Since limitations of the relative percent method of exercise intensity prescription have been reported, such as the lack of ability to account for individual variations, this study assessed the benefits of using the threshold method.
The paper hypothesized that a 1) “threshold based training model” would elicit greater mean changes in cardiorespiratory fitness (as measured by VO2max) when compared to the relative percent method and 2) participants in the threshold based training model group would be more likely to have favorable VO2max responses; while comparatively, participants in the relative percent method group would be more likely to experience a VO2max nonresponse to exercise training
This study found that both exercise intensity prescription methods significantly improve VO2max.
The study also found that the threshold prescription method reduced the variation in responses across individuals, suggesting its potential to enhance training.
Introduction: Cardiorespiratory fitness, measured by VO2max has been used to represent overall health. Exercise intensity is an important factor to get a training effect, and the American College of Sports Medicine recommends a 40-59% heart rate reserve (HHR)/ oxygen uptake reserve (VO2R) intensity to improve and maintain cardiorespiratory fitness, but the percent concept approach has a large range of acceptable percentage and also fails to account for individual metabolic responses to exercise.
Methods: 42 nonsmoking men and women recruited (18-54 yrs). Included if low-to-moderate risks defined by ACSM and sedentary (< 30 min of moderate intensity physical activity 3x/week for at least 3 months), no exercise beyond the requirement for the study. Double-blind study. Randomized into no exercise (n=12) or exercise training groups (n=12 / group). Training performed 30min/d, 5 d/wk for 12 wks. HRR group: relative percent method, intensity prescribed based on the percentages of HHR. ACE-3ZM Threshold group: intensity prescribed according to the VT1 and VT2 thresholds. Resting HR and BP measured. Anthropometric measurements taken: skinfold thickness, weight, and waist circumference. Fasting blood lipid and blood glucose measurements were taken at baseline and post-program. Maximal exercise testing was done using a modified-Balke, pseudo-ramp graded exercise test on a power treadmill. Maximal HR, defined as highest bpm during the test, was used to determine HRR. Ventilatory thresholds (VT1, VT2) determined from graphs of time plotted against relevant respiratory variables.
Results: 36/42 completed study. VO2max increased significantly (p<0.05) in both HHR groupd (1.76 +/- 1.93 mL/kg/min) and ACE-3ZM group (3.93 +/- 0.96 mL/kg/min) relative to control. Significant interaction observed between methods and VO2max change with 41.7 % (5/12) of HHR participants experiencing a favorable change in relative VO2max (Δ > 5.9 %) compared to 100 % (12/12) in the ACE-3ZM group.
The ‘Transformational’ Tymewear Breathing Sensor Hits the Market: Should You Get One?
Article on Velo by Jim Cotton (UK-based reporter focusing on racing, training, and nutrition)
April 18, 2025
Key Points:
The article claims the TymeWear VitalPro device’s prototype, which is in collaboration with Visma-Lease-a-Bike, makes it possible to obtain laboratory-level insight through the handlebars of bikes
In the article, ventilation is noted to be a more reliable indicator of suffering and performance than heart rate and power.
The strap device measures minute ventilation, the total air exchange at the lungs, to determine when athletes switch between aerobic and anaerobic metabolism
The brand is promising “near-lab accuracy” for the VitalPro device
Amateurs often overdo their endurance training, which prevents them from getting the benefits of high-intensity training
Using ventilation metrics gathered through devices like VitalPro can help pinpoint individualized training regimens to make them more effective
Progress can be detected when ventilation metrics are used
Is the Tyme Wear Smart Shirt Reliable and Valid at Detecting Personalized Ventilatory Thresholds in Recreationally Active Individuals?
Gouw et al. (2022)
Key Points:
This was a validation study that assessed the reliability and validity of Tymewear’s smart shirt in detecting individual ventilatory thresholds relative to the Parvo Medics TrueOne 2400.
Ventilatory threshold 1 (VT1) and 2 (VT2), vary depending on the individual, correspond to exercise intensities or workload, and indicate shifts in exercise metabolism.
In a 2-trial assessment, Tymewear’s smart shirt’s ability to detect VT1 and VT2 was less valid with similar reliability relative to its laboratory counterpart.
Tymewear underestimated VT1 workload (p>0.05) and heart rate (p<0.05) for trial 1 and significantly underestimated VT2 workload (p<0.05) and heart rate (p<0.05) in both trials.
However, the suggested threshold-guided exercise intensities for VT1 and VT2 appear to be adequate workloads for most individuals.
While Tymewear’s technology allows for more accessible and affordable data collection, the smart shirt was reported to be unlikely to replace/devalue laboratory testing.
Introduction: Wearable technology consumption has been growing for its potential to provide previously unknown biometric data, which can be used to track fitness, guide training, and collect general health data. Reliability is the consistency of collected data. Validity is how accurately the collected data represents the reality of the measured variables. To test this, a device must be compared to a gold standard.
Methods: Email/word of mouth participant recruitment at Western Colorado University (N=19; 11 males, 8 females). Recreationally active male/female between 18-65 yrs with no pulmonary and cardiovascular conditions. 2 trials of GXT separated by 7-10 days rest. For each trial, pre-test screening questionnaire was completed before the metabolic cart, and Tymewar Smart Shirt ventilation data for 3 breaths were collected. GXT data collected: 1 min standing, 3 min walk at 3MPH, begin running at 3.3 MPH with 0.3 MPH increase every 30s until vocational fatigue, 1 min standing. WearLink’s chest strap heart rate monitor was fitted, and Tymewear’s smart shirt was also fitted with a Tymewear pod attached to the hub of the smart shirt. Anthropometric data collected.
Results: 4 subjects’ data excluded due to equipment error or data loss during testing. The device makes data more accessible and affordable than typical laboratory testing. Tymewear had excellent intraclass correlation coefficient (1CC) >0.9 reliability utilizing timepoint and workload data but moderate 0.9>ICC>0.75 reliability utilizing heart rate. TrueOne exhibited excellent reliability using timepoint, workload, and heart rate. Tymewear underestimated VT1 workload (p>0.05) and heart rate (p<0.05) for trial 1 and underestimated VT2 workload (p<0.05) and heart rate (p<0.05) in both trials. Tymewear’s smart shirt’s ability to detect VT1 and VT2 was less valid with similar reliability relative to its laboratory counterpart. Suggested threshold-guided exercise intensities for VT1 nad VT2 appears to be adequate workloads for most individuals. Tymewear’s smart shirt is unlikely to replace/devalue laboratory testing.
Estimation of ventilatory thresholds during exercise using respiratory wearable sensors
Contreras-Briceno et al. (2024)
Key Points:
This study validated a different respiratory monitor and its algorithms for estimating VT in laboratory and clinical settings.
An ergospirometry analysis of 17 healthy adults was used to validate the RR and VT predictions, while the wearable system was used to evaluate VTs in 107 recreational athletes.
The mean population values were shown to agree with physiological variables that are traditionally used to prescribe exercise regimens, suggesting the respiratory wearables’ usefulness to determine aerobic and anaerobic parameters, which may promise applications in health telemonitoring and human performance.Not a subscriber to the podcast? Click here!
Support the podcast: TriDoc Podcast Patreon site
Need an endurance coach? TriDoc Coaching
Reply