Why Don't Our Feet Swell in the Upright Position?

Rising to the upright position should a priori increase capillaray pressure in the feet by 100 mmHg and cause excessive filtration. Fortunately, frank edema is automatically prevented by arterial vasoconstriction and reduced capillary surface area, by colloid osmotic hydrostatic counterforces in plasma and interstitium, and by increased lymph drainage.