How to make sense of your Apple Watch Heart Rate Variability (HRV) data

A theoretical and practical guide: updated to iOS 13 and WatchOS 6

New to Heart Rate Variability?

What’s new then?

How good is the data?

Heart Rate Variability: rMSSD

It’s all about context

Measuring at the right time: the morning routine

What about using data points automatically collected by the Apple Watch during the night?

Example of 2 nights with different physiological stress levels. While the averages are clearly different, relying on single data points can easily confound the relationship, as there is much variability during a night, due to the circadian rhythm and different sleep stages

What should you do then?

Interpreting your daily measurements

Reduced HRV (higher stress) in response to two very different events: running the new york city marathon, and celebrating New Years. Stress = training + lifestyle.

Getting practical: what do you need to get it done?

HRV4Training app + Breathe for the morning measurement

Set default mode to Health instead of using the Camera or Bluetooth sensors, allow HRV4Training to read from Health, and you are good to go. In the morning, measurements will be taken using the Breathe app, which pushes RR intervals to Health, then you can read the data from HRV4Training, which will interpret it in the context of your historical data.

Founder, Data Science @ouraring Lecturer @VUamsterdam. PhD in Machine Learning, 2x MSc: Sport Science, Computer Science Engineering. Runner

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