Explain the relationship between BP and pedal edema.

If Na is not properly excreted by the kidneys, it accumulates in the body. The hypertensive person has an increased concentration of Na in the blood vessel walls. This would lead to an edematous state within the walls and cause an increase in the resistance to blood flow. There is also an increase in Na in the interstitial spaces. This increase in particles will, by osmosis, draw water into the space. The increase in fluid takes up space, adds weight, and puts pressure on the outside walls of the blood vessels. This causes the heart to pump harder to continue adequate circulation. This edema is usually first evident to the naked eye in the patient's feet, called pedal edema.