I donate plasma twice a week and each time they of course check my blood pressure and heart rate.

Before and after I started dieting, my heart rate was around 90-95. I've recently started adding Jillian's 30 Day Shred in the morning and Turbo Jam in the evening and I'm feeling great and energized.

The problem is now, my heart rate is now at 105-107, deferring me from donating. I've been doing some research and it's an alarming heart rate and I'm a bit worried. Why is this happening???

Overtraining, perhaps?

I went through something similar a year ago. came to find out that my body was fighting off a severe viral infection. I had been sick with a nasty "cold" for about a month and was starting to feel better, but my body was still sick. It actually lasted for about 5 months. My doctor even put me on blood pressure medicine to try to help.

I don't know if you have been ill lately or might be getting sick, but it can make a difference.

Actually I was sick a few weeks ago with a really bad sinus infection. I still have productive coughs occasionally. I didn't think of that!

It's a little high. You might want to get it checked out. High heart rates (and I am thinking in or above the 120-130s here) could be thyroid related or heart-related so worth a professional opinion. If you are experiencing any breathlessness at rest or swelling in the ankles then it is definitely worth getting checked.

On the other hand, my heart rate is 45-50 which is too low and was this when I was 281lbs. I had high BP at the time and the numbers did not add up (in the words of my doctor, I was "clearly not a professional tennis player"). So I had all the tests and they concluded that some people just tick a little slower/faster than others for genetic reasons.