That's a super tough one...I just got a health coach a few months ago...one of her suggestions was that I cut down MAJORLY on my caffeine intake. I gradually cut down on the coffee and diet soda. I hafta say...my pulse used to ALWAYS be at least 140...now it's usually below 100. AND...I don't wake up in the morning w/ the feeling of my heart pounding out of my chest. Also, don't drink caffeine after like 4pm. I know it's not a pill...more of a lifestyle change...and I don't even know if you consume large quantities of caffeine (like I used to)...but I have to say, it made a world of a difference for me.