Do I really need to wear a nose clip during my stress test?

I’m finally getting the tests I’ve needed since October. A stress test and echo cardiogram are schedule for me in ten days. I’m excited because I’m hoping to get an answer to some health problems I’ve had for some time.

I should say I was excited until I read that I’ll need to wear a nose clip and I’ll be breathing into a tube. Is this correct? I have a hard time breathing only through my mouth. On top of this I start to panic, which makes breathing more difficult. I had a hard time during my lung function testing when I had to wear a nose clip. You’ll never catch me scuba diving or snorkeling. I couldn’t handle it. :(

I will be on a treadmill. Can you fill me in on what to expect?