Thanks for all the responses. I will try to provide a little more detail. My breathing is very hard and I feel out of breath...but all this is relative to other runners. People running faster than me and people running at the same pace absolutely are not breathing as hard as me. I am really sucking air! It is clear I am running faster than my aerobic system has been trained for. So, I feel like there is a gap in my training (I am learning and not sophisticated on the various workout types) that is causing this excessively hard breathing compared to my current pace peers and those runners that I aspire to run as fast as.

I have a solid base (I may not be using that term correctly) as I can run for an hour or more at a 9 min/mile pace as a regular workout. I have very good muscle endurance...my legs feel very strong during my races. It is my aerobic system at race pace that is really strained?I think it is strained beyond what would be considered a race effort. This is my weak point and races quickly point out what needs improvement.

In my case, I do not feel there is any medical issue. I feel certain it is a training issue?I am very much a student to the various types of workouts. I have received some good advice here on specific workouts to try (which is what I needed), and I appreciate the great people that have offered their thoughts. Thanks again and any additional comments are welcome!