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Leg Swelling in Aging: What to Know & What to Do - Part 1 of 5


Swelling in the lower legs – known as “lower extremity edema” in medical terms – is a problem that often affects older adults. The good news is that most of the time, it’s annoying, but not terribly dangerous. However, in other cases, swelling in the feet, ankles, or lower legs can be the sign of a new health problem, or a worsening chronic condition.

And, even if it’s “benign” and not related to a dangerous health condition, edema can be a major risk factor for skin breakdown and reduced mobility in aging adults. Since leg swelling becomes so common as people get older, in this article we’ll demystify leg edema and cover the most important things that older adults and families should know about this condition. In particular, we’ll  cover:

  • How does edema happen?

  • Common causes of swollen ankles or legs in aging adults

  • Medications that can cause leg swelling as a side-effect

  • How leg swelling should be medically evaluated

  • How to prevent and treat leg swelling

  • What to know BEFORE going on a “water pill”

How does edema happen?

We notice edema when our shoes are too tight, or we get marks on our ankles from our socks.  But what’s really going on inside the body? Edema happens when fluid moves outside of blood vessels and into what’s called the interstitial spaces of the body. These spaces are also sometimes called the extra-vascular space (which literally just means “outside of blood vessels”), and is basically the moist space between cells, organs, and body parts.

Although you make think of blood vessels as being “waterproof”, physically they are more like a semi-permeable membrane, made of blood vessel cells that usually stay close together, and it’s normal for small quantities of fluid to pass back and forth.

If more fluid than usual passes out of the blood vessels, and this happens in the legs or near the surface of the body, it looks like a swollen or puffy area under the skin.

Fluid can move into the interstitial spaces and cause edema for a few different reasons. The most common causes are

  1. “Leaky” blood vessels: Sometimes the blood vessel cells don’t stick together as tightly as they should. This can allow fluid molecules to slip through the connections between the blood vessel cells (like gaps between the bricks in a wall).

  2. This can happen due to severe infection or inflammation, among other things.

  3. Low levels of protein in the blood: Proteins, such as albumin, help keep fluid inside blood vessels. This is because protein molecules in the blood exert an “osmotic” pressure (also called “oncotic pressure”) that helps retain fluid inside a blood vessel. If protein levels fall in the blood vessel, even if the membrane of the blood vessel is intact, fluid moves outside of the vein or artery to equalize the osmotic pressure across the membrane, and this creates edema.

  4. Some causes of low albumin levels in the blood include certain types of kidney disease, liver disease, and malnutrition.

  5. Fluid overload: If there’s more fluid than usual in the blood vessel, it becomes “overloaded.” The extra fluid will be then end up pushed across the blood vessel wall because of high hydrostatic pressures.

Normally, our kidneys regulate body fluid levels by adjusting the amount of water and salt that is excreted or retained. But if those mechanisms fail or are overwhelmed, edema is often the result. When we look at common causes of edema, keep these different mechanisms in mind.  The cause of the edema will play a major role in deciding on the best course of treatment.

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