Can anyone answer what exactly the relevance of this number means with regards to our disease. My last lung function test was actually better than previous one: FVC 4.87 (98%), FEV1 3.17(84%), FV1/FVC 66%. But my FEF25-75% is quite low at 1.95 (58%). I've been very SOB for quite a while and have not exercised in almost a month. I don't really understand, as even doctor agreed I should be struggling this much with the reported lung function I have. Any insight would be greatly appreciated.