random racing

[beaurline]

It'll also seem though that my heart will race when i'm just standing or even sitting, and i feel palpitations. It never really used to be that noticeable. Then sometimes after i get done working out, or it kind of speeds up a little then slows down, and it does this upon standing or sitting as well, then i'll sometimes feel nauseous or dizzy.

[lagoya]

their are lots of different reasons for hr racing both up and down and i agree with jerry if u give more info we may be able to give a better answer ,but in a healthy setting ,too much caffeine ,stress,dehydratation ,thyroid ,exercise etc .if u feel your heart is kicking up for no reason a holter monitor may show up what is going on during these periods

[Jerry_NJ]

Do you have any numbers for your "racing" HR?  

Working out will cause the HR to go up/down depending on your workout intensity, I"m sure you know.  But your question isn't clear on the conditions that cause you concern.