Swollen feet or ankles are common and they can come from a long list of triggers. “There are probably 50 different things that can cause feet, ankles and legs to swell,” says vascular surgeon Dr Britt H. Tonnessen. Doctors say the key is working out whether swelling is a simple lifestyle issue or a sign that something else needs attention.
Dr Tonnessen explains that the body relies on two main “drainage” systems. Veins move blood from the legs back towards the heart, while the lymphatic system helps shift fluid through the body.
“These two systems work in tandem to get the fluid out of your legs. But when fluid remains pooled in your feet, legs or ankles, that swelling is called oedema,” says Dr Tonnessen.
“Most of the time, foot swelling is actually not a foot problem,” says board-certified podiatrist Tek Fish. “It’s often something else causing the feet to swell.” He points to common triggers such as vein issues, prolonged sitting, pregnancy, kidney issues and infections. Below are a few of the most common reasons your feet puff up, plus what tends to help.
1. You’ve been on (or off) your feet all day
Long days on your feet can leave you with sore, heavy, swollen ankles by evening. Sitting for hours can do it too, especially if your legs hang down for most of the day. Doctors call this dependent oedema, which is swelling driven largely by gravity.
If this sounds like you, start simple: elevate your feet when you get home. Propping your legs on a pillow so your feet sit above heart level can help shift fluid back up.
Dr Tonnessen also recommends compression socks to limit fluid build-up. “They go from the foot to the knee and are a little snugger on the foot and ankle to prevent the accumulation of fluid,” she explains.
2. You’re consuming too much salt
A salty meal can show up in your feet fast. Too much sodium makes the body hold onto water, which can lead to puffiness and swelling.
“I advise my patients to really look at labels of all their food, to see how much sodium is in their diet soda, canned soups, microwave dinners and to consume no more than 2,000 to 2,400 milligrams per day,” says Dr Tonnessen.
A practical approach is to keep the “hidden sodium” culprits in mind (packaged soups, sauces, deli meats, ready meals) and balance saltier meals with potassium-rich whole foods and plenty of water, unless a clinician has told you to limit fluids.
3. You’ve got an injury
Swelling after a sprain, fracture or tendon irritation can be part of the body’s normal healing response, and it usually comes with pain, tenderness or bruising.
Start with the basics. Rest the area, reduce impact, elevate when you can and use cold packs in short bursts early on. Over-the-counter anti-inflammatory medicines such as ibuprofen may help with pain and swelling, but check the label and avoid them if they’re not suitable for you (for example, if you have certain stomach, kidney or heart issues, or you’re taking particular medications).
If pain is severe, swelling is rapidly worsening, you cannot bear weight, or the foot looks deformed, get it assessed.
4. You’ve got a baby on board
Swollen feet and ankles are extremely common in pregnancy. Fluid volume increases, the growing uterus adds pressure that can slow blood return from the legs and hormones can loosen ligaments, which can also change how feet feel and fit.
Helpful moves include gentle walking, regular movement breaks, leg elevation, comfortable shoes and, if your clinician agrees, compression socks.
Call your doctor urgently if swelling is sudden, one-sided, or comes with headaches, nausea, blurred vision, chest pain or shortness of breath, as these can signal issues that need prompt attention.
5. You’re on your period
Hormonal shifts in the days leading up to a period can cause temporary fluid retention, including swollen hands and feet. It usually settles once bleeding starts or shortly after.
If you’re dealing with monthly swelling, focus on the boring-but-effective trio. Move daily, hydrate well and keep sodium in check. If swelling is severe, painful, new for you, or lasts beyond your cycle, it’s worth a GP chat to rule out other causes.
6. You’re carrying extra weight
Pregnancy is not the only scenario that increases pressure in the lower body. Recent weight gain can also affect circulation and lymphatic flow, which can show up as swelling in the feet and ankles.
“If you’re sitting a lot, that extra weight in your belly sits right on the groin area, and that can disrupt the lymphatic flow that drains fluid from your legs,” says Dr Tonnessen. “But even losing just 10 or 20 pounds can make a difference.”
Small shifts help include more movement breaks during the day, gentle walking, leg elevation when you can and support from a GP or dietitian if weight changes feel hard to manage alone.
7. It may be a side effect of medication
Some prescription medicines can cause fluid retention. Examples include some hormonal contraceptives, steroids, some blood pressure medicines (including calcium channel blockers), some antidepressants (including tricyclics and MAO inhibitors) and some diabetes medicines.
If swelling starts soon after a new medicine or a dose change, book a chat with your prescriber or pharmacist. Do not stop a prescribed medicine on your own. Often, a small adjustment, timing change or alternative option can help.
8. You have varicose veins
Varicose veins are common and can appear earlier than many people expect.
“Even people as young as their 20s and 30s can get varicose veins,” says Dr Tonnessen.
They happen when leg veins weaken and the valves that help move blood back toward the heart become less efficient, so blood pools. That can lead to visible veins plus heaviness, aching and swelling around the ankles.
Supportive habits include compression stockings, regular movement, leg elevation for short blocks through the day and strength work that improves calf and leg muscle “pumping”.
9. It may be a blood clot
Sudden swelling in one leg needs urgent attention, especially if it comes with pain, warmth, redness or tenderness. It can be a sign of deep vein thrombosis (DVT).
“This can happen at any age, and it typically happens after someone has been laid up after an injury or hospitalisation, or after a long car ride or aeroplane flight,” says Dr Tonnessen.
DVT is diagnosed with an ultrasound and needs prompt treatment. If you have sudden one-sided leg swelling, seek urgent medical care, particularly if you also have chest pain, shortness of breath or coughing up blood.
10. You may have an infection
Even a small blister or cut can tip into an infection, especially if bacteria get under the skin. Swelling is often paired with redness, warmth, tenderness and sometimes an obvious wound or discharge.
“That usually comes with redness, warmth, and often a wound,” says Dr Fish. “That’s a medical emergency situation, not a ‘wait and see.’”
If the skin looks rapidly worse, feels hot, becomes very painful, or you develop fever or chills, get urgent medical care.
When to seek medical care
Swollen feet are often harmless, but certain patterns need fast follow-up.
Seek urgent medical care if swelling:
- is sudden or severe
- affects only one leg
- comes with significant pain, warmth or redness
- happens with shortness of breath, chest pain, fainting or coughing blood
- follows recent surgery, injury, long travel or prolonged bed rest
If swelling keeps getting worse or comes with symptoms such as shortness of breath, chest pain, or pressure in the chest or abdomen, speak with a doctor urgently. It can sometimes signal heart, kidney, or liver problems, or another issue affecting circulation and fluid drainage.
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