You’ve got to hand it to your feet—they might just be the hardest-working part of your body. They take a beating every day, supporting your body weight and letting you walk, run, jump, stand, and tip-toe. The 26 bones and more than 100 muscles, tendons, and ligaments in each foot and ankle work as a team, carrying you to your job, the gym, and home.
All of this foot action adds up to a lot of wear and tear, so it isn’t a surprise that one of the biggest complaints people have is swollen feet. Feet often puff up a half-size or so because you’re not treating them with the TLC they deserve—say by standing all day or shoving them into too-tight pumps. But swollen feet have other causes too, some of which are serious and serve as red flags to a larger health issue.
So what exactly happens when feet swell? Whether due to pressure, inactivity, injury, or some other cause, circulation to and from your feet slows down, and blood begins to pool in the many blood vessels spread out along your toes, heels, and ankles. Gravity helps this along too, says Dyane Tower, DPM, director of clinical affairs at the American Podiatric Medical Association.
You stand or sit for hours at a time
Counter people, doctors, nurses, and others who work on their feet often end the day feeling like their shoes are too tight. Here’s why: when you don’t move much while standing, the muscles in your legs, ankles, your feet don’t have a chance to contract, causing blood flow to and from your feet to slow down.
The same thing happens to people who sit for long stretches. Reduced blood flow triggers swelling, making shoes feel tight and uncomfortable. And if you’re sitting cross-legged, pinched blood vessels cause by the position you’re in can aggravate the swelling.
While annoying, this kind of end-of-the-day swelling is usually not indicative of a larger problem and should go away once you’ve walked around or uncrossed your legs. “There are no hard and fast guidelines, but if you’re on your feet all day long, it’s reasonable to sit five minutes every hour, or put your legs up,” says Jason Johanning, MD, professor of vascular surgery, University of Nebraska Medical Center, Omaha.
If the swelling persists or you can’t take breaks from standing or sitting, give compression stockings a try. “Compression stockings work the same way as walking and add a bit of pumping action to keep blood the flowing a little faster,” says Roy Silverstein, MD, vice president of the American Society of Hematology and chair of the department of medicine at the Medical College of Wisconsin.
You consume too much salt
The sodium in salt is the biggest dietary culprit when it comes to retaining water in general. So it only makes sense that it can lead to foot swelling as well, says Dr. Johanning. The American Heart Associationrecommends that adults take in no more than 2,300 mg of sodium every day, or about a teaspoon of salt per day.
Thing is, most of the sodium people consume comes not from the salt shaker but from processed and restaurant food, where it’s hidden among a list of ingredients and used as a preservative. Prime sources include cold cuts, processed snacks, frozen meals, canned soups, bread, and salad dressing. Go easy on all of these, and instead focus on sodium-free items such as fruits, vegetables, nuts, seeds and whole grains while avoiding processed foods.
You’re pregnant
For many women, swollen feet are an inevitable part of pregnancy. It typically begins in the second trimester. “As the baby grows, it presses on the pelvic veins, and you get a little bit of compromised circulation,” says Jill Rabin, MD, co-chief, division of ambulatory care, Women’s Health Programs-PCAP Services, Northwell Health, New Hyde Park, New York. Hormonal shifts also get some of the blame. During pregnancy, your body produces the hormone relaxin, which causes pelvic and foot joints and ligaments to relax and enlarge.
Foot swelling tends to get worse as pregnancy progresses, especially toward the end of the day and when the temperature outside is high. Usually the swelling is nothing to worry about. But if it comes on rapidly, especially in your hands and face, call the doctor. This could be a sign of a potentially life-threatening condition called preeclampsia, which leads to rapid-onset high blood pressure that can dangerous to mother and baby.
To ease swollen feet that are a normal part of pregnancy, don’t stand or sit for extended periods of time, and put your feet up periodically above your heart to get circulating going again. Compression stockings can help too, as can exercise, putting cold compresses on your feet, and sleeping on your side.
“If you have a big belly from pregnancy, lying on your back causes the blood vessels to compress,” explains Dr. Rabin. “That makes it more difficult for the circulation to get back to the heart and will sometimes cause some of the fluid in the veins to see out.”
You weigh too much
Add swollen feet to the list of health-related side effects of being
overweight or obese. “One of the most common reasons people have
problems with [swollen feet] is that they’re just too big,” says Britt
Marcussen, MD, assistant professor of family medicine at the University
of Iowa Carver College of Medicine. “Their bellies have all this fat,
and the fat compresses the circulation in the legs—and there’s back
pressure downstream from that and their legs swell. It’s like pinching a
garden hose.”
Your ankle or foot is injured
Maybe you sprained your ankle during a gym workout, or you overextended yourself while running or playing with your kids and ended up with a stress fracture of the leg or toe. Injuries like these will cause swelling in and around your feet.
“The body’s response [to an acute injury] is inflammation,” explains Tower. “The blood goes down to that area of the heel and brings cells and fluid.” Ultimately, the cells and fluid help the area heal. But in the meantime, it can make your foot seem extra-large.
Surgery on your leg, ankle, or foot also causes swelling. Your doctor will likely recommend that after the procedure, you control the swelling by elevating your feet, icing the area, and refraining from putting any weight on the limb or foot.
You’re dealing with hormone fluctuations
You know how bloated you can feel the week before your period? That waterlogged feeling is the normal result of hormone fluctuations after ovulation, when premenstrual syndrome sets in. PMS can also be to blame for swollen feet, if it happens at this point in your cycle. “You can feel a little puffier or swollen for sure,” says Dr. Marcussen. “It’s noticeable in the legs and feet, where it tends to pool because of gravity.”
Hormonal changes triggered by hormonal contraception or hormone replacement therapy can also contribute to swelling in various parts of the body, including your feet.
You’re taking medication that causes swelling
Hormonal contraception and hormone replacement therapy aren’t the only meds that can cause foot swelling. So can many other drugs, and usually for different reasons. Pills to control blood sugar in people who have diabetes—like Avandia (rosiglitazone) or Actos (pioglitazone)—make it harder to get sodium out of the body, which leads to swelling.
The heart drugs known as direct vasodilators can also cause it. “Vasodilation” means the drugs help open up the blood vessels to make blood flow more freely. Examples are Loniten (minoxidil) and Apresoline (hydralazine). Calcium channel blockers widen blood vessels by relaxing the muscles in vessel walls. This can also cause foot swelling, as can angiotensin receptor blockers, which prevent sodium from being flushed out of your body.
Those drugs are available only by prescription, but over-the-counter meds are to blame for swelling too. Nonsteroidal anti-inflammatory drugs like ibuprofen (Advil, Motrin) can make swelling worse in people who already have heart or liver failure because they cause the body to hold on to sodium.
Other drugs can cause your feet to swell without any obvious explanation. These include anti-seizure drugs like gabapentin, chemotherapy drugs like docetaxel and cisplatin, and medications to treat Parkinson’s Disease like Mirapex (pramipexole) and Requip (ropinirole).
You have an infection
Foot swelling that hurts could be caused by a skin infection. Having the bacterial infection cellulitis on the feet and legs could be behind it. “The swelling is usually associated with red, hot, sore skin,” says Dr. Marcussen.
People with diabetes and peripheral vascular disease are at a higher risk of infection, and any infections they do get can escalate quickly because of the reduced blood flow to the body’s extremities, including the feet. If you have diabetic neuropathy, a common complication of diabetes that affects nerve function, an infection might be hard to notice . . . and therefore get worse quickly.
Infections can also happen after the skin is broken, leaving an opening for bacteria to enter, or even from shoes that don’t fit or ingrown toenails. Certain diseases, among them lupus and rheumatoid arthritis, also increase the risk of a foot infection.
Simple measures like moisturizing foot skin regularly so it remains supple and not easily broken can help prevent infections. Antibiotics will usually clear up bacterial infections that have already set in, but it’s important to see your doctor to get a prescription quickly.
You have lymphedema
Lymphedema is a condition that occurs when something goes wrong with your lymphatic system, which is part of your immune system. Lymphatic fluid carries infection-fighting white blood cells to different parts of the body. Clusters of lymph nodes throughout your body control the travel of this fluid. But if your lymph nodes have been damaged or removed, say during surgery for cancer, the fluid won’t drain properly—and that causes swelling.
Generally, swelling in the feet happens when the pelvic lymph nodes, which control lymph movement in your legs and feet, are injured or removed. “The lymphatic vessels are very thin and pliable, so when you operate in the groin area, even with meticulous surgical care, they can be injured and can create an obstruction blocking the return of the lymphatic fluid,” says Dr. Johanning.
Occasionally lymphedema is an inherited condition; often it’s brought on by obesity, cancer or an infection. If you suspect your swollen feet are caused by any of these conditions, check in with your doctor. In the meantime, try compression stockings and moving around as much as possible.
Your heart isn’t pumping enough blood
You wouldn’t think they were connected, but swollen feet are a not-uncommon sign of congestive heart failure. Heart failure doesn’t mean your heart stops working, just that your heart can’t pump enough blood. This means blood backs up in the veins, leading to fluid buildup.
The location of the swelling can help you rule out heart failure: usually swelling in the feet points to right-sided heart failure. And if you have heart failure, swelling in your feet is usually more pronounced than the swelling that happens after you’ve been standing on your feet all day. If it lasts long enough, you may also get pitting, which is when the skin stays indented after you put pressure on it. Says Dr. Marcussen: “If this and shortness of breath dramatically worsen, and you gain more than five pounds in a day, this should be concerning.”
You’ve developed a blood clot
You’ve probably heard of it happening to people on planes: after sitting for a long time without moving their legs, they develop swelling and pain on one side . . . and later find out that they have a dangerous blood clot known as deep vein thrombosis. If caught in time, it can be treated. But often it isn’t, and the clot can break off and travel to the lungs, where it cuts off the oxygen supply and can be lethal.
How does foot swelling play into this? “The swelling is caused by the presence of the clot,” says Dr. Silverstein. “The clot causes pressure to increase behind the area of obstruction, and that increased pressure pushes the fluids in the blood out of the veins into the tissues. “
While anyone who sits for long periods can develop a blood clot, certain factors boost your risk, including obesity, smoking, being pregnant, having heart failure, kidney conditions, a previous clot, cancer, or taking certain medications, such as birth control pills.
Though a clot that’s caused foot swelling doesn’t always have other symptoms, typically you’ll feel pain in your leg as well. “The most common presentation is significant pain and discomfort in the calf region with associated swelling of that limb,” says Dr. Johanning. If you these symptoms strike without explanation, notify your doctor ASAP, or head for the emergency room.
The strategies that prevent your feet from swelling from other reasons can also help prevent blood clots.
You’re in kidney failure
Your kidneys are responsible for balancing fluids in your body and moving fluid you don’t need out of your system. When one or both aren’t functioning properly, you might end up with swollen feet.
“Normally people [with foot swelling] go home and put their feet up, and the body reabsorbs that little bit of extra fluid, and the kidneys just get rid of it,” explains Dr. Marcussen. “[With] kidney problems, your body has trouble getting rid of that fluid, then that swelling is more marked and more dramatic. A lot of people have swelling other places too, like their hands and face.”
You would think that treatment for kidney disease would help the problem, but not so with dialysis, which is often required for advanced cases of kidney failure. Dialysis machines are like artificial kidneys, performing the same tasks that your kidneys no longer can. Even on dialysis, though, your body can’t get rid of enough fluid.
This is when medications can help. “People who have heart failure or kidney problems are often put on diuretics,” says Dr. Marcussen, of medications that increase the amount of water and salt you excrete in your urine. “Basically they help the kidneys dump fluid.”
You have liver disease
Cirrhosis of the liver means it has developed scarring, perhaps from hepatitis or from drinking too much alcohol for too many years. The scarring interferes with blood flow to and in the liver. This causes high blood pressure in the veins going into the liver (called portal hypertension), potentially leading to swelling in both the legs and feet but also in the abdomen (called ascites). Cirrhosis also interferes with production of a protein called albumin, another factor contributing to foot swelling.
Drugs, namely diuretics, and lifestyle measures like limiting salt can help with symptoms, including foot swelling. Although reducing the amount of swelling in either the legs or the abdomen won’t help your liver get better, it can make movement and breathing easier. Always do this under the care of your doctor, as people with liver failure need to get rid of the excess water slowly.
Other signs of cirrhosis include swelling in your abdomen, feeling tired, bleeding and bruising easily, nausea, and having yellow-tinted skin and eyes. Treatment usually involves medications lifestyle changes and even a liver transplant.