Dear Hiltjo:
Welcome to our Community! You are our first patient from Holland! I hope that your therapy with T & T is successful in preventing all future episodes of SCLS, but if it is not, then insist that your doctors try putting you on a therapy based on monthly infusions of IVIG.
As concerns your original question, no, there is no medical evidence that formerly being engaged in sport activities made anybody vulnerable to the onset of SCLS -- or to having episodes of SCLS, specifically.
Otherwise, of course, SCLS would be far more common than it is -- there are many people who practice sports -- and we wouldn't have any SCLS patients doing sports after being diagnosed and treated, whereas in fact we do.
I have personally met or corresponded with many patients, and most were not avid sportsmen/women before getting SCLS, and yet I know of a few episode-free patients on T & T and IVIG therapies who are active sportsmen (see the profiles of _rnuara_ and _claude53_, respectively).
Therefore, if you are currently incapable of handling sports, it could be because you are still having more frequent but smaller-scale episodes of SCLS -- in which case, of course, your organs are not getting the oxygen that they need, which is why you feel weak.
You can have your blood checked anytime you feel weak to see if you are experiencing hypotension (a temporary drop in blood pressure), hemoconcentration (a temporary increase in the concentration of red blood cells), and hypoalbuminemia (a temporary drop in the level of albumin) -- namely, to see if you are having an episode of SCLS. And if you are, then it is likely that the T & T therapy is NOT working.
Incidentally, please fill out as much detail as possible on your profile page (e.g., your gender, the symptoms you experienced, the treatments you received, the hospital that treated you, any temporary or permanent injury that you suffered, etc.). The information patients provide makes it easier for us all to have answers to questions like the ones you asked.