Breathlessness but no lung issues

[medicalmystery]

This is a bit frustrating really. So there's someone who enjoys singing, but over the past year or two whenever she does it makes her lightheaded/faint.

The answer is probably to stop singing! But
A - that would be a shame
B - it doesn't seem normal to have this response and could mean that there's something seriously wrong.

She's been to the GP who has done various lung function tests including CT scans, had heart issues checked and there are no problems to be found.

Is there anything else that they might be missing to eliminate as a cause? Or tests they should do? Or is there any specialism that may be able to investigate further, despite all lung/heart tests being negative?

Any ideas gratefully received!

Anaemia?

Nope she's had a full MOT and the GP is at a loss. Not sure where to turn now so turned to mumsnet in case there's been anything overlooked etc.

Is she breathing from the chest instead of diaphragm when singing?

Oops OP you've had a name change fail!

Ha! Oops!

Never mind, doesn't matter too much

Thyroid issues. It is possible for thyroid levels to be ‘normal’ and to have issues. I am sure someone can explain better, but breathlessness can be a problem with autoimmune things.

Singing lesson with a teacher who specialises in technique and clinical issues? They do exist. Could be she is doing something weird with her breathing while singing that is causing the problem (assuming she is only ever breathless while singing)>