On the street I run 3.5 to 4 miles about every other day. Recently I've taken up trail running on the weekends. I'm in Washington with mountains all over. So I'll get the dog, hike up a four to five mile climb then run down. Today I was running down what would have been a 6.5 mile after a 4.5 mile climb. Most of the down was in the sun and when I got into the shade I started to feel funny. Tingling on the surface, and chilled. I was tired, but not panting, heart not pounding, just in the middle of what for me is a good run. It felt as though maybe I wasn't getting enough oxygen to my extremities, but I did still have feeling in my toes and fingers.
I guess my question is for people whom push themselves, has anyone else experienced that? Ever find a cause? I do have low BP just due to running... Fat and lazy it's 120/80 and in shape I've seen it as low as 105/54 and @ 52 bpm. Thoughts? Dr. or chalk it up to my current limit?