Pilots develop scars on their arms and legs where the bladders have literally popped their blood vessels. Modern fighters also pump pressurised oxygen directly into the lungs. Forgetting to breathe at mach three can be bad for your long term health. Scientists who studied dragonflies found that they were able to perform 30-G turns with relative impunity. The reason lies with the dragonfly's fragility.
Every organ is encased in fluid.
When blood transfers under the effect of gravity, so does the liquid, creating a counter pressure. The result is like encasing a pilot in a fluid womb. What's more the suit clearly works. It's like sex with Viagra. The suit is also lighter and more comfortable because it doesn't need complex electronic operation or pressurisation.