What is medically known as "shortness of breath"?
Correct answer: Dyspnea

Lionessa
The last time I was in the Rocky Mountains, I felt okay in the Salt Lake valley, but riding up one of the steep canyons, I grew shorter and shorter of breath the higher we went. I couldn't stay at the top of the canyon. Altitude sickness is real to those who live near sea-level.

Marcy
I always experience that despnea so when I try to sing I always have to pause for a while

CoolE
Nobody calls it that except doctors. Wheezing is also a shortness of breath!