Increased heart rate is a common side effect. Unless you have some pre-existing heart problem, you shouldn't have anything to worry about.

Another side effect of the cannabis high is becoming more aware of your body and it's functions. Your heart is beating faster and you notice it more than you would normally. If you begin to get paranoid about it, your heart rate will increase even more, in turn feeding your paranoia, etc.

It's something you get used to and stop noticing as long as you don't let your imagination run away with you.
BlueBlazer Reviewed by BlueBlazer on . Nervous Nervous Hey guys I tryed weed sober for the first time and got a little paranoid, my heart was going quite fast and didn't like that at all! What if I had to run? My heart was already going at a running pace! I'm a newbie really I liked the feeling just the heart bit! Is it safe? Is there a way for me to not have such a fast beat when smoking weed? Rating: 5