Any time I have alcohol my heart feels like its racing, even after one beer. Is there any reason why this is happening?
Alcohol is a drug that does, in some individuals, result in activation, with a tachycardic (rapid heart beat) response. It is ironically true for some sedatives, and can result in a perception of anxiety and uneasiness, even progressing to a panic reaction. The same is true and quite common for marijuana.
You may find that other forms of alcohol are less bothersome to you, but there is no way to lessen or prevent this physiologic response to the drug effect of alcohol.