My 17 Year Old Daughter Is A Runner And Swimmer.

My 17 year old daughter is a runner and swimmer. For the past year her lower arms and legs grow heavy, eventually getting to the point of loss of feeling when she competes. When she finishes a race she can not stand up/pull herself out of the pool. Her heart rate will shoot up to 200 during a race. A heart specialist has ruled out heart problems. What type of doctor should she seek help from?