Continuing my adventures in counting steps, one day this week I strapped on three different devices to compare step counts:
My iPhone SE in my pocket
An older Fitbit Surge on my left hand
My Withings Steel HR on my right arm
... for three different activities:
Morning dog walk
A 3 mile run-walk on a treadmill
My 'travel steps' from the time I got in my car to head to the airport through the flight, rental car pickup and until I reached my hotel
I expected to see differences, but I believed that the two watches would be closely correlated and the iPhone would be the outlier. At a minimum, I expected consistent differences. But, both of my hypotheses were wrong:
It was very interesting to me that the closest alignment was during the treadmill run, but, as I thought about this more, it makes sense as that was the only activity that didn't have any extraneous factors that could alter the step count, such as:
On the dog walk, I was only walking one dog and had her leash in my hand, generally my right hand where my Withings watch was. That could explain the difference with my left arm, but doesn't explain why my iPhone was so close to my Withings watch.
During my 'travel steps' I was dragging my rollerbag luggage around the airport, to the rental car and into the hotel. I did try to, roughly by time, switch between pulling it with each hand and both watch counters are within 2% of each other. As both watches, though, were well below the iPhone, it makes me hypothesize that a 'watch-based' counter might not track as well when you are pulling/pushing luggage as your arm will have more limited movement.
I realize this is, yet again, an extremely limited sample size and no deep conclusions can be reached. Whatever tracker you choose, I think the key is establishing a baseline with that tracker and then, assuming you want steps as a component of your fitness, working to maintain or exceed that baseline.