Halfway through my workout, the watch said check your monitor! and it did not register heart rate (it showed 00) and stopped counting calories. Is this serious? I've only had it two months. I have an email in to the seller but I'm wondering f this is a common issue
Mine started doing this repeatedly after about 9 months of use. Eventually it would only read 00, no matter how wet the sensors were or where I placed it. Fortunately, I bought it from REI and they were awesome about exchanging it for a new one. The replacement lasted 18 months with no issues.