Hello Dr. Grief. My name is Alexander and I am a 20 year old male. I am about 6'2 183 lbs and I consider myself to be pretty healthy. I have been donating blood plasma for several months now and, for the most part, I have not run into any problems during the check-ins. However, from time to time my pulse will be too high and I won't be allowed to donate. A couple weeks ago I went in and my pulse was 114, and the last time I went in (a few days ago) it was right at 100. I do smoke cigarettes at least every other day although I rarely smoke more than 2 or 3 cigs/day. I also drink coffee several times a week, but I make sure to never smoke nor drink coffee the morning before I go in to donate. I really need the $ to pay for gas so it is critical that my pulse is below 100 when I go in tomorrow. Aside from basic breathing exercises before and while my pulse is being taken, are there any other methods that are available to me to help ensure that my pulse won't be too high when I go in?