after 37 minutes felt total body lightness

Question
I just started training for a triathlon this week. Two days swimming, two biking, and two running with some transitioning mixed in. I'm 35, 5'9 150 lbs in good shape. I've had both ACL's reconstruted, and one ankle has screws. I play hard...snowboard, volleyball, basketball, paintball...sports that have a lot of stop and go. I have stayed away from running because I my knees. MY QUESTION: I was running on a treadmill for 45 minutes, I noticed at the 37 minute mark that I felt very light from my hairline to my feet...my breathing was easier and I picked up my pace easily. I almost felt numb...yet alert. This feeling continued until I took my shower right afterwards. Should I be concerned...what could cause this and do I need to do something different?

Answer
Hi Angela
It appears to me a great sign your in real good shape since the body is just flowing and the arterial network is clean and responsive.When your in great shape everything is smooth,relaxed,flowing,responsive.I see no reason to do anything different,but be carefull you don't go over the edge.There is a fine line as i'm sure you know.If you have other questions Angela just get in touch.

All the best

John