The FLOWBIO Sensor is the world’s most accurate sweat sensor, independently validated to deliver lab precision.
Built to analyse your sweat in real time, it measures how much fluid and sodium you’re losing — and syncs with the FLOWBIO App to turn that data into clear, personalised hydration recommendations. So you know what to drink, when, and how much.
The Hydration Planner creates session-specific strategies that adapt to your workout intensity, duration, and the conditions. You’ll get precise fluid and sodium recommendations before each session or race.
After each session, log what you consumed and select your favourite electrolyte brands — including Precision Fuel & Hydration, SiS, Maurten, and others — to keep your data accurate and your strategy personalised.
The sensor can be worn on your upper arm with the included FLOWBIO strap, or paired with your HR chest strap. With a 100-hour battery life, USB-C charging, and seamless integration with Garmin, Zwift, Wahoo, and Coros, it fits into the way you already train. Unlike other sensors, the FLOWBIO system is a one-time purchase — no subscriptions.
FLOWBIO SWEAT SENSOR
I’ve just started using the device, and my goal is to build a full table of my sweat data across training zones and climates. Even after just a few sessions, I surprised to see the differences — I always thought sweat rate was more linear, but FLOWBIO showed me how much intensity and climate change the picture.
Léa Riccoboni
Pro Triathlete
"Having FLOWBIO predict my race day hydration strategy has been game changing. No longer am I guessing on how much to drink and it’s shown just how important electrolytes are when racing.
At National Champs it finally felt like I was going into a road race with a plan for my hydration strategy which allowed me to focus on racing”.
Xan Crees
British CX Champion
"Winning my age group at Ironman Cairns 2025. It was the first time I completed a full Ironman without cramping or fading — I stayed steady and in control from start to finish. FLOWBIO helped me understand my real hydration and sodium needs and adjust my hydration accordingly. I stayed consistent, clear-headed, and was able to finish strong."
Laurent Travers
Amateur Ironman Age-group Winner
FLOWBIO makes sweat measurable. In just a few simple steps, the sensor captures your sweat data and turns it into personalised insights you can act on before, during, and after every session.
If you have any questions, you are always welcome to contact us. We'll get back to you as soon as possible, within 24 hours on weekdays.
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The Sensor captures your sweat and analysis its contents. Proprietary algorithms use the sensor data to estimate your sweat rate and sodium loss. The data is shown on the FLOWBIO App, offering recovery and preparation suggestions and tips to optimise your performance.
Please note that prices shown for customers from outside the United Kingdom exclude VAT or relevant import duties. For customers in the UK, VAT is added at checkout.
Currently, data from the Sensor is accessible only during cycling, running or walking activities. We plan to expand and include other sports as we grow. If you are interested in using our Sensor for a different modality please get in touch here.
The Sensor is designed to be worn on an existing heart rate monitor. We support both optical arm-based monitors and chest straps, offering flexibility in wearing the Sensor either on the upper arm or on your back.
The Sensor measures your sweat rate and sodium loss, helping you optimise your recovery and prepare for training and events by ensuring you replace and bring the necessary fluid and electrolytes.
Our latest data has indicated that we are 90% accurate in lab based conditions. In the field we achieve accuracies up to 83% for our sodium with as little as 23 mg difference (that is 6x less than a pinch of salt). Our fluid loss is 73% accurate with as little as 250mL difference to in-field gold standards. If you are interested in learning more about the accuracy of the system behind the Sensor, you can request our whitepaper here.
You can exercise without your phone nearby, but for syncing the Sensor and viewing your data, having your mobile device is essential.
At present, using the FLOWBIO System requires a fitness tracker integrated with the Companion App. We currently support the following integrations:
