new Pixel Watch 3With a display that’s twice as bright as the previous generation and now in a new 45mm size, smaller bezels and new color options, the inside of the Pixel Watch 3 is just as exciting as the outside, with improvements to how Fitbit uses metrics to give you information about your health and fitness.
Our methodology and approach to building these metrics is grounded in sports medicine, and we’re continually learning and incorporating it into Fitbit. Pixel Watch 3 includes an all-new “Daily Readiness” algorithm and two new tools, “Cardio Load” and “Target Load,” to help you understand how your body is recovering from everyday activities.
The team that created these new metrics brought deep expertise in fitness and medicine to their work. Cathy Speed is a professor of sports medicine and human performance at Cardiff Met University and a senior clinical specialist on the Fitbit team. She also has a background in elite and high-performance sports medicine. “We have all the tools for elite athletes,” she says of her past work. “We monitor them. They are the experts on their own bodies, and we can answer the question, ‘What should I do to train in the smartest way I can today?’” With these Fitbit updates, Cathy and her team aimed to put this kind of information in the hands of everyone, not just elite athletes. Here, we look at what was done to improve Fitbit’s preparation and recovery tracking, and what led the team to introduce two new scores.
Fine-tuning your daily preparations
Fitbit introduced its Daily Readiness Score in 2021 as a way to understand how recovered your body is. “In the first version of Daily Readiness, the score incorporated not only activity, but also heart rate and sleep data,” says Cathy, so the app can let users know how ready (or not) they are to workout.
With the launch of the Pixel Watch 3, the Fitbit team wanted to tweak their algorithm to better match key signs of your body’s recovery. To do this, they started with the Pixel Watch 3’s multi-path heart rate sensor. “This gives us a really accurate picture of your heart rate, which is key to understanding heart rate variability – the variability in the timing between your heartbeats,” says Cathy. “HRV is a very sensitive indicator of physiological recovery and can tell you a lot. It’s like a very quiet warning sign that your body is starting to struggle to recover or is starting to recover long before you’re fully aware of it.”
Daily Readiness takes into account HRV as well as sleep, and has added a new metric to its algorithm – resting heart rate, which is known to reflect the long-term effects of illness – to give a more comprehensive picture of your body’s recovery. But the team also added Cardio Load and Target Load, which they felt could help people better understand their training and know how hard they should be working out.
Introducing Cardio Load and Target Load
Cardio Load (which appears alongside Daily Readiness in the Fitbit app) helps you understand how hard your heart is working throughout the day, not just during activity. It also shows your training status based on your activity history, showing if you’re maintaining or improving your fitness, or if you’re under-training or over-training. Then there’s Target Load, which recommends how much activity you should do today based on your recent Cardio Load and training status and readiness. “We could have added these data points to the Daily Readiness algorithm to create a Daily Readiness Score, but that would have been a bit of a black box. Instead, it gives you a comprehensive picture of your body’s recovery and, as a result, an actionable target for how much you should do,” explains Cathy.
