Shortness of breath and fatigue are my two main issues. My situation is somewhat unique in that I had a double lung transplant in 2022. I was diagnosed with COVID in 2023 which is when I first started experiencing symptoms. My lungs and heart are very good. So I went to multiple specialists trying to get a diagnosis for my symptoms.
I was finally given an I-CEPT , Invasive Cardiopulmonary Exercise Test. This yielded 2 important results that help explain my symptoms. 1) the blood returning to my heart had an unexpectedly HIGH level of oxygen. This indicated that the mitochondria in my skeletal muscles were not effectively utilizing oxygen so my muscles were being starved of oxygen, sort of like a 6 cylinder engine running on only 3 cylinders.
2) with exercise, my vascular system was not returning enough blood to the heart. This is called cardiac preload insufficiency. The heart is pumping but there is not enough blood returning to the heart to keep up with demand. Consequently, one feels breathless and dizzy.
TREATMENT. This is all symptomatic treatment. 1) For the mitochondria I've been prescribed amino acid powder, alpha lipoic acid, and B vitamins. Limited help. 2) For blood return insufficiency I wear compression socks, take salt tablets, midodrine which increases blood pressure , and fluodrocortisone which helps increase blood volume.
I also try to exercise using my recumbent bike in 15 minute sessions 2-3 times a day as tolerated.
Hope my experience may give you some ideas. I live my life in 15-20 minute bursts followed by extended rest.