salt doesn't speed up the heart reat. It can raise the blood pressure but only if you already have blood pressure problems. for example katey has blood pressure issues, salt affects her. I don't have any blood pressure issues and i can have 10 times as much salt as her with no effects on my BP.
as for adding salt to coffee, we used to do that @ one place i worked because it took the bitterness away from the coffee. just a dash will do.