I m a 23 year old female and I have been smoking marijuana pretty much daily, and heavily since I was around 19. I ve never really had any problems, other than some anxiety issues but those were older issues. Now every once in a while I can feel my heart fluttering. My heart rate usually goes up when this happens and it s slightly harder to breath, but usually only when I m doing something physical. I am just wondering if I should be worried and see a doctor or if this is normal for a smoker. I smoke cigarettes also if that matters.