Here is just an observation of mine... I have been smoking for about 4 years or so (maybe more). I've noticed that anxiety is associated with an elevated heart rate. I can tell by simply checking my own pulse that on average, my heart rate is higher than it used to be. I used to be around 65 BPM, and now i'm seeing anywhere from 70 to 90 depending on how hard I work my body. Is the fact that my lungs are having a harder time pumping oxygen to my system, and thus increasing my heart rate to accommodate contribute to my anxiety? Pick your brains a little bit...