I either walk/run for 40 min, use elliptical for 30 min or ride my bicycle for 30-60 minutes, I have had all the heart tests, low cholestrol, bp normal that I monitor (high when I go to dr!) I take no medicines only fish oil, wheat grass, coq10, daily, calcium...and I am 54 yrs old. Afterand during exercise, my face is very pale, I don't feel bad...most of the time I keep my heart rate anywhere from 60-70%....just wondering if I need to be concerned?