Source: mioglobal
To eliminate the need for a chest strap MIO use optical sensing (if you are techy – photoplesmographic technology).
In optical sensing, a light is shone onto the skin, allowing the measurement of blood flow through the capillaries and the determination of heart rate. The technology has existed for some years – the heart rate monitor finger clip you may see at the hospital uses it. Until now, the technology could not be used on athletes, or anyone moving around, because the clutter of other signals generated by noise from movement would interfere with the readings being captured by the optical sensor. MIO Alpha solves this with a built-in accelerometer to compensate for signal disturbances generated by motion, while noise-filtration software ensures a clear signal is delivered to the Alpha’s micro-processor. Optimizing all of these aspects required significant software development, testing and multiple design iterations. The result is a device that achieved a 0.99 correlation with EKG in independent testing at San Francisco State University.
MIO Alpha provides continuous, EKG-accurate heart rate readings at running speeds higher than 14 mph.
Now you know!
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Last Updated on 13 November 2025 by the5krunner
My favourite kit and nutrition
- Maurten — the race nutrition trusted by elite athletes. Gels and drink mix engineered to be easy on the stomach.
- Garmin 90-degree charging adapter — the small adapter that keeps your charging cable tidy at the stem. Essential for race day.
- Garmin charging puck — the fastest and most reliable way to top up your Garmin before a session.
- Ravemen FR300 — front light that mounts directly under your Garmin or Wahoo head unit. Keeps your bars clean and your beam pointed where it matters.
- Garmin Varia RTL515 — radar rear light that alerts you to vehicles approaching from behind. Pairs with your Edge or Garmin watch.
- Stryd — the footpod that brings running power to your Garmin. The single most useful running upgrade I have made.
- Favero Assioma Pro RS2 — the power meter pedals most serious cyclists end up choosing. Accurate, easy to move between bikes.
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tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID
