Sweat is data.
And we proved it.
Most hydration tech asks you to take its word for it. FLOWBIO put its sensor through an independent, peer-reviewed validation study — measured against the same gold-standard methods sport-science labs use. Here's the evidence, in full.
Not a marketing claim. A published study.
FLOWBIO's decision to seek independent academic validation reflects a simple position: hydration data should not be assumed, inferred or internally benchmarked. It should be measured, compared and published under scientific scrutiny.
Independent validation of the FLOWBIO wearable sweat sensor against laboratory reference methods
The study, at a glance.
+ hot & humidtwo lab climates tested
Measured against the gold standards.
Twenty-three recreationally active, endurance-trained adults completed ~75-minute indoor cycling sessions at a demanding but sustainable intensity, in both hot-dry and hot-humid conditions, wearing the FLOWBIO Sensor on the upper arm. Its readings were compared side-by-side with the reference methods sport science trusts:
- Pre- and post-exercise body-mass change — the laboratory gold standard for whole-body sweat (fluid) loss.
- Laboratory flame photometry — the gold standard for sweat sodium concentration.
- LAQUAtwin Na-11 portable analyser — the field standard commonly used in endurance sport for sweat sodium.
- The FLOWBIO Sensor — worn throughout, measuring in real time as athletes rode.
What the data showed.
As good as the lab reference.
Sweat loss estimated by the FLOWBIO Sensor showed no significant difference from values calculated by body-mass change — the laboratory gold standard. The wearable's estimates closely matched the reference.
Matched the field gold standard.
The FLOWBIO Sensor produced sweat-sodium values comparable to the LAQUAtwin Na-11 field standard. Both read slightly lower than lab flame photometry, but were consistent with each other.
The numbers FLOWBIO stands behind.
Accuracy figures as reported by FLOWBIO from their latest field and laboratory data.
How it actually measures your sweat.
No needle. No patch to post off.
The FLOWBIO Sensor is reusable and non-patch. It collects sweat through a tiny channel, driven by the natural pressure of your own sweat glands — so unlike some rivals, there's no needle and no lab sample to send away. It's worn on the upper arm, on the FLOWBIO strap or integrated with arm/chest heart-rate straps.
Data in, strategy out — via AHi®.
Proprietary algorithms turn the raw signal into your sweat rate and sodium loss. Advanced Hydration Intelligence (AHi) then blends that with effort and environment — temperature and intensity — to produce a personalised plan: what to drink, how much, and when.
Because hydration decides races.
Hydration influences endurance performance, recovery and heat tolerance — and sweat rate and sodium loss shift with intensity, heat, humidity, duration and your own physiology. Averages and calculators can't track that. The research on the cost of getting it wrong is not subtle:
General hydration figures drawn from published sports-science research; sensor findings from the FLOWBIO validation study.
References
- Bandiera D., de Bardonnèche J., Margout-Jantac D., Dubois L., El Allaoui N., Rubio J.S.E., Aubin J-C., Racinais S., Tessitore A., Pitsiladis Y. Independent validation of the FLOWBIO wearable sweat sensor. Frontiers in Physiology, 2025. DOI: 10.3389/fphys.2025.1717275. University of Rome "Foro Italico" & CREPS Montpellier, with Human Telemetrics.
- Published sports-science literature on hydration, dehydration and sweat-sodium variability in endurance athletes.
Ride on your numbers, not the average.
You've read the evidence. Now measure your own sweat and let STACK'D turn it into the exact plan for your next race. STACK'D is an MTBApp product, launching soon.
Buy the FLOWBIO Sensor