Just curious where most people are.
The best way to measure your resting heart rate is the morning after a rest day, before you have breakfast. Sit or lay down, relax for a few minutes, then count your heart beats for a full minute. Some people think 15s is enough but I don't agree, as being off by 1 beat is an error of 4 beats per minute. Go the full minute, or more if you want to be really accurate.
Going PB lowered my resting HR by 10bpm, and low carb appears to have shaved another 3-4bpm off that.