Hello starfrance,
I surmise that your cardiologist refers to Landis, the cyclist who was disqualified from the Tour de France in 2006. He produced various reasons for his abnormal results, one excuse is dehydration.
With CLS, you can certainly lose 43% of your blood volume ... But when the attack changes, this serum comes flooding back into your veins.
In my case, I average a 38% loss, which last 4-6 hours, and gets better. This 2 l loss is enough to cause severe shock. The important part is that the red cells remain, unlike blood loss from trauma, and they are still there to carry oxygen.
The committee at the time decided for Landis. If he had, for instance, 2ng per litre of blood of banned testosterone, and he dehydrated 50%, then the reading would be 2ng per half litre, or 4ng per litre.. Double the acceptable reading.... But for various reasons, this does not hold up with the rigid testing. I do not presume to judge him.. Just give and example.
Good luck
John