Trace every breath.
A wireless breath analyzer that measures the oxygen you take in and the carbon dioxide you breathe out, on every breath.1 VO2max and thresholds from your own gas exchange, not a wrist estimate.
Run a sports-science lab or longevity clinic? See the validation partner programme →- O2 + CO2
- Both gases measured
- Every breath
- Breath-by-breath analysis
- Wireless
- No hoses, no cart
- On-mask
- Computed on the device
01Film · 27 s · original score
Meet VenTracer.
A breath, the design, six parts, the numbers. Twenty-seven seconds, no narration.
Renders of a design concept; on-screen values are example data. Plays muted until you press Play with sound, or turn on site sound.
02Why measure · 80 s · sound on
Why a watch number isn't enough.
Estimates, formula zones and the lab you can't book: what's missing today, and why breath is the measurement.
Narrated, with English captions. Charts are illustrative; sources below.
Transcript and sourcesRead the narration and check the evidence
Your watch gives you a VO2max number. It's an estimate. Checked against lab tests, watch estimates are often off by 5 to 10%. They tend to read high if you're less fit, and low if you're very fit. Two people can see the same number, and have very different engines. Training zones are often worse. Many still start from 220 minus your age, a formula that's typically off by about a dozen beats a minute. Your real thresholds aren't in your pulse. They're in your breath: the points where carbon dioxide breaks away from oxygen. Measuring breath has meant a lab. A cart, a booking, a hose to the wall. So most people never test, and athletes rarely test in their own sport. And fitness matters beyond sport. In a study of more than 120,000 patients, low fitness was linked to higher mortality, as strongly as smoking or diabetes. VenTracer puts the breath measurement on the mask. Oxygen and carbon dioxide, every breath, wherever you train. And we'll prove it against a lab cart before we claim a number. Measured, not estimated. VenTracer.
- Watch VO2max error and bias by fitness: Železnik Mežan L. Accuracy of wearables for determining the maximal oxygen uptake and lactate threshold: a qualitative systematic review. Front. Sports Act. Living, 2025.
- 220 − age error: Sarzynski MA et al. Measured maximal heart rates compared to commonly used age-based prediction equations in the HERITAGE Family Study. Am. J. Hum. Biol., 2013. Standard error of estimate 12.4 bpm.
- Fitness and mortality: Mandsager K et al. Association of cardiorespiratory fitness with long-term mortality among adults undergoing exercise treadmill testing. JAMA Netw. Open, 2018. 122,007 patients; an association, not proof of cause.
03Estimated vs measured
A watch estimates. VenTracer measures.
Wearables infer VO2max from heart rate and pace. Lab and portable gas-analysis systems measure it from gas exchange, but they are expensive and mostly stay in the lab. VenTracer is being built to put that measurement on your face, wherever you train.
| VenTracer IN DEV | Lab or portable system | Wrist wearable | |
|---|---|---|---|
| VO2max | Measured | Measured | Estimated |
| Oxygen (O2) | Measured | Measured | Not measured |
| Carbon dioxide (CO2) | Measured | Measured | Not measured |
| Thresholds | From gas exchange | From gas exchange | Estimated |
| Where you test | Anywhere you train | In the lab | Anywhere |
| Hoses or cart | None | Yes | None |
| Typical cost | Not announced | US$20,000 and up | Comes with the watch |
04How it works
Two gases. Every breath.
Air goes in at 20.9% oxygen. It comes back out with less oxygen and more carbon dioxide. That difference, multiplied by how much air you move, is your oxygen uptake: VO2.
- Breathe.
The breath flow sensor in the tube measures the volume of every inhale and exhale.
- Sample.
A dual-gas breath core reads oxygen and carbon dioxide beside the airway and corrects for pressure, temperature and humidity.
- Compute.
The on-mask processor aligns gas and flow breath by breath to give VO2, VCO2 and RER.
- Stream.
Results reach the VenTracer app over Bluetooth LE while you train.
05In short
VenTracer in three answers.
What is VenTracer?
VenTracer is a wireless VO2max breath analyzer in development by Caropet Technologies Pvt. Ltd. (Rapid Circuitry), Hyderabad, India. It measures oxygen, carbon dioxide and breath flow on every breath to calculate VO2max and ventilatory thresholds, instead of estimating them from heart rate.
Is VenTracer available?
Not yet. VenTracer is in development. Engineering prototypes are planned for 2027, followed by validation and pilot units for sports-science labs and longevity clinics. Pricing has not been announced.
Who is VenTracer for?
Sports-science labs and longevity clinics first: teams that already test VO2max and thresholds and want to do it outside the lab, in the athlete's own sport. Coaches and serious endurance athletes follow once validation is published.
06Go deeper
Pick your way in.
Take it apart.
Scroll through an exploded view of the analyzer, then read the preliminary specifications.
Design and specs → ScienceHow breath becomes VO2max.
Gas exchange, the V-slope method, ventilatory thresholds and how an incremental test works.
Read the science → Labs and clinics · priorityField testing without a cart.
What VenTracer is being built to do for sports-science labs and longevity clinics, and how we'll validate it.
For professionals →07Validation
Validation comes first.
Early units will be tested side by side with laboratory reference systems at partner labs. No accuracy figure appears on this site until those results are published.
See the validation plan and what VenTracer can't do yet →Test the first units with us.
Sports-science labs and longevity clinics: test early VenTracer units side by side with your own reference equipment.