Yawning through cardio?!

Yawning through cardio?

For some reason that I can not understand I yawn while doing cardio, like i'm not getting enough oxygen or something. I was taught how to breathe during cardio by a trainer... to be able to expand my lung capacity i guess. I've always had a problem doing long cardio like running, and eliptical... i always feel like i'm never going to get air.
I was checked for breathing problems when i was younger and the doctor didn't see any issues.

This doesnt happen while i'm weight training .. only when i do cardio type actions, including stairs at home, or long distance walking.

What can I do?

Yawning is a way for you to increase your oxygen intake. Normal resting breathing uses an amount of air called tidal volume. When you yawn, you utilize your inspiratory reserve volume...the amount of air that can be maximally inspired.

The fact that you are yawning specifically with cardio and not with weight trainig may be indicative of the fact that you are either working beyond your capacity or not taking in an adequate amount of oxygen.

If you are becoming short of breath during exercise, I would go back and get checked again by a physician.

If you are really concerned, see if your trainer carries a pulse oximeter which would measure your oxygen saturation with excerise. If you are not getting enough, you may need more work on your breathing technique, are working too hard, or there may be an underlying problem.