The exact origins of National Swim a Lap Day are a bit of a mystery. Like many quirky holidays, it seems to have popped up as a fun way to celebrate the start of summer and promote physical fitness.

Certain tracker features are now ubiquitous: step counting, distance calculation, sleep tracking, and most recently, heart rate monitoring. But one of the more elusive features—swim tracking—is often ...

I LIKE THE IDEA of lap swimming. But the act of swimming is better in my head than in the water. During the first lap, I tell myself things are going pretty well. I can keep this up. After a couple ...