Prepregnancy, my lowest heart rate has been 76 bpm while truly relaxed. Now, after giving birth two months ago, I have a resting heart rate of 56/60. I feel tired, but am a new mom who works 24 hr shifts at EMS, so I find that normal. I have had a tingling sensation to rt shoulderblade for about 3 weeks that is also strange. Otherwise, I feel normal. Any normal reason for my change in heart rate? It is regular, but have only discovered this today by checking pulse ox equipment on ambulance. I double checked by taking it manually.