I am a 17 year old female and I consider myself to have a relatively healthy lifestyle (I don t smoke , rarely drink and have a healthy diet ). The other day in school my heart suddenly began beating very rapidly and my fingers started to tingle, as though I couldn t feel them properly; after about 15 minutes my heart beat went back to normal, but now I am concerned about what this might mean. It has happened on a few occasions before, although not for some months, and last time it happened, I also felt extremely dizzy and light-headed. It happens rarely but usually there is nothing to bring it on, it just happens suddenly (for example, when it happened recently I was simply walking around school!). I would appreciate any advice that you could give me.