Just to educate all you non-medicals out there. Arteries have thick walls composed of both smooth muscle and elastic fibres - while they can be compressed it takes some pressure to do so and you will have to use positive pressure to keep it closed. When you release the artery it will spring back to its normal size even without blood in it. A vein is the opposite - the only thing that keeps it open is the pressure of the blood in it. Take out the blood and it collapses.
Now take the scenario of tight leg straps:
Ateries and veins run alongside one another. The arteries supplying the leg and veins draining the leg are large - app 1cm in diameter. There are more than one but the largest ones, the femoral artery and vein run anteriorly from the pelvis down into the deeper anterior thigh muscles. With a really tight legstrap the veins will be pushed close before the arteries are effected - i.e blood continues flowing down and into the leg but cannot flow upwards out of the leg to the inferior vena cava as the vein is compressed shut by the leg strap. The nett effect is that blood continues to accumulate in the legs at a steady rate while venous outflow is impeded.
The end result is a decrease in blood flow back to the heart which means there is eventually less blood available to supply the brain with oxygen resulting in a faint (reduced bllod volume) - similar to orthostatic hypotension.
Have you ever seen a parade where soldiers are standing on parade for hours without moving and some of them faint - due to increased blood stasis in the legs and decreased heart output to the brain (as soon as they collapse and are lying on the ground the blood flow to the heart increases and they recover quickly). Remember venous flow from the legs is reliant on muscle contractions in the lower leg - standing motionless for hours at a time causes blood to pool in the leg veins. Pretty simple.
The effect of tight leg straps could easily cause similar problems and would be compounded if you spiraled down - the G forces would cause more blood to pool in the veins of the legs and the tight leg straps would impede blood flow out of the legs while arterial flow to the leg is maintained. As soon as you land and release pressure on the occluded vessel - return to normal. Of course muscle movement will also help.
We are not all built anatomically the same - different arm and leg lengths, obese, thin, different harness sizes. We may wear different clothes each time we are on the DZ and wear our harness. All these factors may be variable from day to day, jump to jump.
Bottom line it is entirely feasible that the cause of her problems are too tight leg straps from an ill fitting harness. The fact she did a few spirals could have contributed. Also the fact she hadn't eaten all day may have been a small contributing factor. Nevertheless having a full medical won't harm anyone but I doubt they will find anything "wrong" with her.
Some of the advice given in previous postings is excellent. Like alter body position in straps under canopy, let a master rigger alter her harness etc. I would also like to suggest she move her legs while hanging under harnes even if its only contracting/relaxing her calf muscles to assist blood flow out of her legs.
Hope the above helps.
Cheers
Rich
(oh I am a medical doctor by the way - in fact a specialist pathologist - for those who have never heard of me before). ---------------------------------------
Everything that happens to you in life is your teacher. The secret is to learn to sit at the feet of your life and be taught.