BPM Calendar - Plotting HR vs Calendar Events

"BPM APP Icon"

This post is the first attempt to begin to document past projects or prototypes that have not been shared outside a small group of friends. I’m hoping the process will help reflect on the work I completed or even motivate me to finish some of them. 😂

How to leverage HR Data and Apple Watch for more than fitness

I like to collect interesting sources of data, especially about myself, and use them to make better decisions.

A few years ago, I purchased an Apple Watch Series 4. I liked the design and the ability to get notifications, but my favorite thing was the built in HR sensor(Close second was the button to make your phone beep). The native Workouts and Health app are great to keep track of workouts and have a good metric of your intensity by looking at your avg HR and ranges.

The Apple Watch HR sensor does not continuously record HR readings at a high frequency. It only records at about 1HZ when a workout is active. If you look at my previous post I leveraged that knowledge to get high frequency data for the entire day for my wedding. If you are not in a workout the watch records every 15 minutes to calculate resting HR.

Once upon a time in a conference room far away….I had just completed a lunch workout and was limping through a brutal meeting. I was receiving harsh and critical feedback from a coworker. It was horrible, the details are fuzzy now, but I walked out of that conference room feeling dejected and exhausted.

I then looked down at my watch and realized I hadn’t stopped my lunch workout. I clicked complete and glanced at the summary statistics. I was shocked.

During lunch I did an intense cardio workout on a rowing machine. My HR maxed out during the meeting…

That’s when I was inspired to Make BPM Calendar. It would be an iOS app that would overlay HR data over your calendar events. Giving the user interesting data points on how their body was reacting to particular people or topics. My hypothesis being that HR is highly correlated to interesting unquantifiable feelings like stress and excitement.

Working Prototype Screenshot



I was able to quickly make a simple iOS app with a single table view of all your calendar events. The app would then pull all of your HR data in the same period and match it against the calendar event times providing summary statistics.

This worked quite well, but most events would only have one or two data points since they were 30 minutes in length and a workout was not active in that time period.

I could not figure out how to automatically have a workout initiated during every calendar event. I also did not know how to do this without messing up my workout data. Maybe Apple has since made a flag to enable higher frequency HR collection?

Another option is to just start an “Other” workout at the beginning of everyday, but that would also mess up your ring stats.

Current Status

I never got BPM Calendar to what I wanted it’s MVP to look like. So I never released it into the app store.

If anyone finds this idea interesting or would want to assist me on working on this I am open to an open source/team effort.

· viz, iOS, quantified self, Swift, project