Behind the Research: Why We Tested Smart Swim 2 Against ECG and Wrist-Based Heart Rate Monitors

Shortly after launching our Smart Swim 1 goggles back in 2019, we instantly had a lot of interest and requests asking for the ability to see real-time heart rate in our goggles augmented reality display, while swimming.

Our journey to integrated heart rate

We quickly set about working on the ability to pair a compatible Polar heart rate monitor (OH1 or Verity Sense) with our Smart Swim 1 goggles so swimmers could see their heart rate live while they swam, for the first time ever.

Fast-forward to Smart Swim 2, during the design process it was abundantly clear that integrated heart rate had to be a feature on our next-generation goggles, and our clever industrial design and machine learning teams set about bringing this idea to life.

Taking our queues from the positioning of the Polar sensors when paired with the FORM Smart Swim 1 goggles, we landed on the temples as the ideal location to accurately get our heart rate readings from - with the temporal arteries providing great blood flow and access to fit a sensor.

During our development process, we also took the opportunity to compare heart rate data measured from our new integrated heart rate sensor and temple location versus the gold standard, ECG chest-mounted heart rate straps, and commonly worn wrist-based sports watches with optical heart rate sensors.

The benefits of swimming with accurate heart rate

Heart rate training is becoming increasingly popular for endurance athletes to optimize their fitness and performance. Being able to accurately track your heart rate while swimming adds more precision to your training and helps you track your overall improvements in the water.

Accurate heart rate tracking enhances training precision, allowing swimmers to set their heart rate zones and execute workouts that cater to individual physiology and training goals, providing flexibility in setting and adhering to intensity targets.

Effective heart rate training requires both accurate and consistent measurement of real-time heart rate. The gold standard for both is an ECG-based chest-worn heart rate strap. However, ECG straps have no ability on their own to deliver data in real-time to an athlete. Instead, all data is reviewed post-swim on a mobile device or desktop platform.

Conducting our first white paper

When it came to developing our integrated heart rate solution for Smart Swim 2, data accuracy was at the forefront of our minds, as it is with all the features we deliver.

We had two main objectives that we wanted to find out:

  1. The accuracy of the FORM Smart Swim 2 goggles' heart rate during swimming compared to the gold standard ECG heart rate chest strap used by athletes. 

  2. How FORM Smart Swim 2 goggles' heart rate accuracy compares to wrist-based heart rate devices that endurance athletes routinely wear.


Study 1: Validating FORM Smart Swim 2 Goggles

Thirty-one participants wore the FORM Smart Swim 2 goggles and a chest strap during their swim. Each participant swam a prescribed 500m workout that was loaded onto the FORM Smart Swim 2 goggles. The workout varied in interval lengths and intensities.

Depending on the participants' swimming experience some swam backstroke and breaststroke in addition to freestyle. To prevent the chest strap from sliding or coming off during the swim, women wore a one-piece swimsuit, and the chest strap was knotted in place so the fastener would not slide around for men.

The FORM Smart Swim 2 goggles were worn under the swim cap, and it was ensured that hair was not interfering with the goggles’ heart rate sensor. The FORM Smart Swim 2 goggles straps were at a comfortable tightness that prevented the goggles from moving too much during the swim.

Study 2: Comparing FORM Smart Swim 2 Goggles to Wrist-Based Heart Rate

Twelve out of the 31 participants in Study 1 also wore a leading swimming watch with a built-in optical heart sensor on their chosen wrist. The twelve participants had equal male and female representation and ranged in age from 20 to 40 years old.


FORM Smart Swim 2 goggles were found to be a highly valid measure of heart rate.

  • FORM Smart Swim 2 goggles demonstrate an overall accuracy rate of 97% in monitoring an individual's true heart rate compared to an ECG chest strap.

  • FORM Smart Swim 2 goggles exhibit an average deviation of +/- 4 beats per minute (bpm) in heart rate measurement compared to an ECG chest strap.

  • In contrast, wrist-based heart rate monitoring displays a variance of +/-10 bpm compared to an ECG chest strap.


In Conclusion

Our FORM Smart Swim 2 goggles can be used as a highly accurate heart rate device. Compared to the commonly used wristwatch heart rate monitor, the FORM Smart Swim 2 is more accurate by ~7 BPM. Moreover, the augmented reality display unique to FORM’s goggles provides swimmers with real-time heart rates that they can monitor continuously. Workouts that are designed using FORM’s Workout Builder can incorporate heart rate zones as another way to accurately infer effort levels when swimming. As such, the FORM Smart Swim 2 goggles are an effective way to add heart rate training into every swimmer’s training plan.

Interested in checking out the full white paper. Click here.


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