For several months I have been experiencing bouts of almost
fainting combined with a thumping heartbeat which I feel in my head as well as my chest. Sometimes this is combined with shortness of breath. This can happen when I am sitting down or when I am standing up. When it happens I feel the need to stop whatever I am doing and wait for it to pass. I find this very distressing, as I am not sure what is going to happen. I am a 40 year old woman, do not smoke, and am not overweight.