Heart rate when running

Hi!! I’ve been running for years and have never really looked much into heart rate monitoring, but have recently been reading more articles about targeted heart rate when training…. My typical heart rate during my runs is around 180 - which is obviously super high & during the last half marathon I ran my average was 187 BPM. It doesn’t sound like this is normal/ recommended - does anyone have tips/suggestions on how to fix this? Or does this just mean I need to cut back/ slow down a bit ?!