iPhone Cycling Health Data Update

Last autumn many cyclists noticed pedaling a bicycle with the iPhone 6 in a pocket counted towards steps in the Health app as noted in my post in December. Besides a concern about duplicated data, my interest is in the problem space of detecting cycling vs walking/running in the general case. A third-party app dedicated to recording activities updates Health app, but the pedometer continuing to record steps created duplicated data. Below is a screen capture of the Health app on December 11 showing my 27-mile rides on the 8th and 10th with a strikingly large distance in “Walking + Running” compared to the 9th and 11th.

Above is how the charts in Health app appeared with significantly high walking/running distance (extra 5.2 miles walked during a 27-mile ride) on the two cycling days in December in iOS 8.1.

an improvement with iOS 8.2

After the 8.2 update for iOS, I noticed the “Walking + Running Distance” in Health app appeared lower than after previous bike rides, but still higher than expected. Today’s ride shows an extra 2 miles walked during the same 27-mile ride taken in December.

Note: I use Cyclemeter to record my cycling and jogging activities. My phone rests in my pocket or backpack on most rides, but for two rides I mounted the iPhone on the handlebar with no discernible difference in results.

The above screen capture of Health app shows an improvement.

• Blue circles: includes 2.25-mile jog
• Green cicle: includes 11-mile run
• Red circles: cycling

Data on the 9th is taken immediately after my morning bike ride. The only day I didn’t jog or cycle was on Easter (5th).

Above is a screen capture of Health app showing April 9th. Notice the three data points for cycling match with three in walking with an improvement since iOS 8.1. The 9th is data using iOS 8.3 and before that, 8.2.

Let’s take a look at “Flights Climbed” in Health app.

Sure enough high peaks on cycling days (circled in red), both the same 27-mile ride with 580 feet of elevation gain and 590-foot descent.

In the above screen capture from Health app, I circled the day I went on an 18-mile ride in the woods with a 3,300-foot elevation gain and 3,200-foot descent. Look at the height of that peak! Granted I did walk a few short hills, but not around 300 flights-of-stairs worth.

Another important note is that Cyclemeter’s pedometer does not agree with steps in Health app on cycling days. Other days are in agreement. Below is a side-by-side comparison with Cyclemeter on left and Health app on right.

It seems the iPhone pedometer counts floors climbed for some cycling elevation changes in addition to extra steps taken. My elevation gain of 3,200 feet on the March 30th ride is equivalent to a 295-story building which appears close on the Health app graph. The 587-foot descent on today’s ride would be about 55 flights, and Health app shows 64. I imagine the grade of the hill and speed may factor into if the iPhone records a flight walked. If there are 15 steps in a flight of stairs then 64 flights would be 960 steps. Health app shows 3,907 more steps than Cyclemeter. Naturally hills on roads have a lower slope than a staircase.

summary

As of iOS 8.3 there is an improvement over 8.1, but the iPhone 6 continues to record steps while cycling in addition to counting flights taken for cycling elevation changes. Best to use third-party apps which compensate the pedometer while cycling such as Cyclemeter.