Hi Evelyn
I don't know the answer to your question but I get weaken legs without any warning, I figured it was from the nerve pain of my fibromyalgia. Still waiting to talk to pain management clinic, will ask when they call.
Sometimes I have almost fallen when it occurs. I will massage my legs while sitting down which helps a bit.
Take care

Hi being in pain causes breathlessness also being tired and stressed x

Thank you MAUIT I fig it was to do with Fibro just went to lock door wheezing and out of breath. It does make sense. hugs Evelyn

Back in 2019, I mentioned to my primary doctor that I lose my breath, just walking to my kitchen from my living room and it’s just a few steps away. She immediately made me see a cardiologist and I got EKG and other stress test— all turned out negative. The doctor said my heart is fine, but something is causing the loss of breath and fatigue. I even started flaring up while I was doing the stress test in the treadmill.
I think it’s all related to the chronic fatigue syndrome of Fibromyalgia, which is still a mystery.

I have stenosis and Ankylosing Spondylitis and they both cause these symptoms aling with fibro.
Best to consult your doctor and get some scans