I've been consistently running for the past 3-4 years or so. This past spring I did a half marathon and have been doing 5k's in around 25:00. I have been running actively 3-4 days per week, 3-5 miles each time. However, in the past few weeks (especially during cross country practices and intervals) I have been unable to catch my breath, yet I don't feel tired. I was doing fine earlier this year and was satisfied with my running, and I do not know what is happening for me to feel like all this progress has been for nothing? Any suggestions or breathing exercises or something so I can feel normal again?
It's possible you may have developed exercise-induced asthma, or you have allergies that are affecting your breathing. One sign of this would be wheezing. Try posting in The Med Tent. There are a couple people responding post there who may be able to give you a better answer.
This (or something akin to it) happened to me a few years back, when I ran my adrenals down. Your adrenals and your respiration are intimately linked. If your training has been consistent, with no big increases in either pace or distance, I might ask if you are under other unusual physical, mental or emotional stress right now. These things can combine and conspire to run your adrenals down.
I deal with labored breathing on an on-going basis and have made strides (no pun intended) with nutrition, supplements, change of locality for better air quality, and most importantly for me, deep relaxation and quality sleep.
What Len said is true: Exercise-Induced Athma, in my meager opinion, is actually a symptom of adrenal fatigue.
He is also right about allergens: When I vaccuum my apartment at least twice a week, I run better!