Before I began wearing fitness watches, I ran with Runtastic or Strava and my phone's GPS, which had no proper heart rate data. I knew of chest heart rate monitors, but the discomfort and inconvenience — not to mention the high prices — made them unappealing. I only wish I'd had something like the COROS Heart Rate Monitor during those years, instead.
Arm-based heart rate monitors fall between chest and wrist-based HRMs in accuracy but arguably win for comfort. It's something you strap on and forget about, especially convenient for gym-goers who don't want a wristwatch interfering with exercises and weights. And even if you wear a watch, a strap gives you the certainty of accurate data without worrying about a perfectly tight, flat-on-wrist fit.
