Hi there. I'm a 21 year old, active healthy female. I run and play basketball and have always been very athletic. However, I have major problems when it comes to going up stairs. I'm not sure if its the pressure change that my body has to deal with in such a quick amount of time or what. But no matter how short (or long) the stairs are, after I walk up stairs it feels as if my legs are being compressed, I lose sensation and it kind of tingles/tickles/hurts. It is an odd sensation to describe, but it forces me to stop walking and bend over or sit until it goes away. If I try to walk, I collapse. I have mitral valve prolapse and I'm 6' tall. Doctors haven't been able to find anything wrong with me. I have great BP and no other existing conditions.