Feet swell because fluid collects in the tissue faster than the body moves it away. Gravity works against you all day, and the feet are the lowest point.
Most swelling is ordinary. Some is not, and the difference is worth knowing.
Ordinary swelling
Both feet, worse at the end of the day, better by morning, and explained by something — long standing, a long flight, hot weather, a salty meal, pregnancy, or a day sitting still. It leaves a brief dent when pressed but recovers.
Swelling that needs a doctor
- One foot or leg only, especially with warmth, redness or calf pain — this can indicate a clot and is urgent.
- Sudden swelling, or swelling with breathlessness or chest discomfort — urgent.
- Swelling that does not improve overnight.
- Skin that is tight, shiny, weeping or breaking down.
- Swelling alongside a new medication.
- Any swelling in a diabetic foot, particularly with warmth — see diabetic foot care.
Persistent swelling in both legs can reflect heart, kidney or liver function and deserves proper assessment rather than home management.
What reduces everyday swelling
Elevation does more than anything else, and most people do not do it properly. The feet need to be above hip height, not just up on a stool. Fifteen to twenty minutes, two or three times a day.
Movement matters as much. The calf muscle is what pumps blood back up the leg; sitting still switches the pump off. Ankle circles and calf raises every half hour do real work.
Soaks and compresses
Epsom salt draws fluid out of swollen tissue by osmosis — half a cup in a basin, twenty minutes, then elevate. Juniper berry is the traditional choice for fluid retention and pairs well with elevation. Ginger and lemon oil both reduce the inflammatory side.
For an inflamed, hot swelling, use a cool compress rather than a warm soak.
Everyday adjustments
Reduce salt, drink enough water — dehydration makes the body retain more — avoid tight socks with elastic that leaves a mark, and get up regularly on long journeys.
In pregnancy, swelling is expected, but sudden swelling in the face or hands, or a sharp increase, should be reported the same day. See pregnancy and foot care.
More on swollen feet and juniper berry.
The test you can do yourself
Press a thumb firmly into the swollen area, just above the ankle bone, and hold for about five seconds. Then take it away and watch.
If a dent remains and fills in slowly, that is pitting oedema — fluid sitting in the tissue. If the skin springs straight back, the swelling is something else, which might be inflammation, injury or a lymphatic problem. It is a crude test and it does not give you a diagnosis, but it is genuinely useful information to hand a clinician, and it tells you whether elevation is likely to help.
The other thing worth tracking is whether it resolves overnight. Ordinary gravitational swelling is close to gone by morning and rebuilds through the day. Swelling that is still there when you wake has a different cause and should be assessed.
Take a photograph of both feet side by side. Asymmetry is easy to miss when you are looking at your own legs from above, and it is one of the details that most changes how urgently a swollen leg is treated.