You will notice this isn't a temp chart but a basal heart rate chart (if you have a Fitbit you may recognize it). My bpms fluctuate throughout my cycle. It has been this way since February. This month my period is late and my chart looks promising. I am 7 days late. Now for normal cycles, my bpm would plummet at my period until ovulation then it would shift upwards. Then it would peak and then start to fall as my period spotting came about. I thought it was interesting, so it's another tool in the belt, but isn't dependent on time and remembering.

Just to note when it says period is when spotting started, my flow started two days later which is when I really count my cycles my o happened on CD 18 which is when I was SHOW and with loads of EWCM. I used the checking for confirmation since like bbt it only tells you after the fact things like ovulation. Hope this helps anyone with a Fitbit.