I am a 46 yr old female who exercise 3-4times weekly. About 10 days ago I started having a fluttery feeling in my chest, similar to when I have caffeine, (I only have the occasional caf bev). My heart rate and respiration rates remain stable, when I go for a brisk walk the feeling is gone. I can feel it most when sitting still. I have no other s/s such as headache or loss of energy, in fact I wake up earlier, with more energy. Could this be peri menopause ?