I'm 5'4", weigh 125, and I've been told that I have the blood pressure of a teenager (no lie, a nurse actually told me that one time, after taking it, and I'm 40). I think it (your face turning red) just happens to some people. Regarding what I said earlier about my face getting red after strength training, I'm sure that has happened, although it hasn't gotten really red, but it was probably after a heavy lower body workout, because of my heart rate getting high (like in PS SL&A).