When my ibs is at its worse ill get symtons of anxiety(fight or flight) without all the mental workup. Then my chest gets tight and its harder to take a deep belly breath. Then your having breathings issues. Try humming. Hum at a low tone inbetween breaths for as long as you can. (Like on the drive to work). That stimulates the vagus nerve around your vocal cords which calms down your nervous system. Allowing your chest to relax making breathing easier.

Yes I get shortness of breath when I exercise.

Rapid heartbeat to the EXTREME! Kinda freaks me out - it beats hard, fast and fluttery.....been concerned.....my GI dr appt isn't for another 6 weeks.....wondering if this is just another bit of IBS-D.....?

I get short of breathe when I try to do too much too fast

I have rapid heartbeat. Just my anxiety that gives me fits. Which gives my IBS fits. Vicious circle.