I have palpatations - diagnosed as a benign rapid heartbeat normally induced by alcohol (though I've found that not getting a reality good night's sleep before a ride contributes to it as well.) I'm supposed to keep to one drink a day. Sadly I do not. It's my one vice but the more work I've done on improving and building cardiovascular conditioning and core and body strength, the less I notice it. I take magnesium citrate once a day as recommended by my cardiologist, and do not drink too much, if at all, a day or two of a longish ride.