I had required Pulmonary Function Test (PFT) this week. The test is supposed to determine whether my breathing is limited by abdominal fat preventing full expansion of lungs. I have Obstructive Sleep Apnea on BiPAP for 23 years with excess fat around neck and in throat. During PFT I had trouble inhaling and exhaling quickly because obstruction in throat. My Arterial Blood Gas was totally normal so I am obviously able to breathe to meet my needs at rest. But I have restriction of my lung capacity by belly fat. I am only 5 foot 1 inch tall and female so lungs are smaller as well. My BMI is 44 but my weight was 240 pounds (now 220) so I don't weigh 500 pounds.

This all explains why I have such a hard time breathing during exertion. Get short of breath with mild walking so exercising has always been difficult. I just cannot move enough air with my lungs during exercise. Hoping weight loss will greatly improve this so I can exercise.

Was so relieved that there was a anatomic reason for my inability to exercise. Was so sick of people saying I just needed to exercise to lose weight. In reality, I need to lose weight so I can exercise. Some people (even doctors) just don't understand. End of rant.

This is interesting. I know someone that last year sounded as though she was going to die just walking very short distances, maybe she had the same thing

That sounds like me 100%. Everything was tested heart etc. I was scheduled for Pulmonary testing but cancelled because I really think it is because there just isn't enough room for my lungs to work correctly. My cardiologist said the same thing. I am also 5' 1" and short waisted and BMI 50. I am scheduled for DS surgery around mid-April. Hopefully, that will work. Good luck !