--- title: "Fluid Retention Explained: Why Your Body Holds On to Water and the Six Places It Settles" description: "Fluid retention explained: why your body holds on to water, why your ankles, face, belly, hands and breasts swell, and when swelling needs a GP." author: Dr Marina Nani (Editor-in-Chief) date: 2026-11-10T17:00:00.526Z updated: 2026-11-10T17:00:00.574Z canonical: https://richhealthmagazine.com/article/fluid-retention-explained image: https://cdn.nanimediahouse.com/pexels-8845436.webp categories: Health, Everyday Wellness content_type: Guide publication: Rich Health Magazine schema_type: Article --- Your socks leave a deep ring around your ankles by the evening. Your rings feel tight on a hot afternoon, and your face looks fuller in the mirror first thing in the morning than it does by lunchtime. All three are signs of fluid retention, the build-up of water in the spaces between your cells, which doctors call oedema. Most of the time it is harmless and goes down on its own. It can also be uncomfortable, it can move the scales by a kilo or more from one day to the next, and now and then it is a sign that your heart, kidneys or liver need attention. Your body already runs its own detox for excess fluid, through your kidneys, your veins and your lymphatic system, and a few everyday habits help those routes work better. Here is how fluid retention happens, where it most often collects and what helps each pattern drain. ## What Fluid Retention Is Water makes up around half to 60% of your body weight. About two thirds of it sits inside your cells. Most of the rest is in your blood and in the fluid that bathes your tissues, called interstitial fluid. Your smallest blood vessels, the capillaries, leak by design. Every day around 20 litres of fluid seeps out of them into your tissues, carrying oxygen and nutrients to your cells. Your capillaries draw about 17 litres straight back in. Your lymphatic system, a network of thin vessels that runs alongside your veins, collects the remaining three litres or so and returns them to your bloodstream near your collarbones. Fluid retention happens when more fluid seeps out than your capillaries and lymph vessels take back. The extra water collects in your tissues, and you see it as puffiness, tightness or a dent that stays in your skin after you press it. ## How Your Kidneys, Hormones and Lymph Decide Where Water Goes Three systems set the balance between the water you need and the water you carry around. **Your kidneys set the total.** Water follows sodium, so after a salty meal your kidneys hold on to extra water to keep the level of sodium in your blood steady. A hormone from your adrenal glands called aldosterone tells your kidneys to keep sodium, and a hormone from your brain called antidiuretic hormone tells them to keep water. Heat, dehydration and stress all raise the amounts of these hormones you release. Changes in oestrogen and progesterone across your menstrual cycle also affect how much salt and water your kidneys keep, which is why many women feel puffier in the days before a period. **Your blood vessels set how much leaks out.** Gravity raises the pressure inside the veins of your lower legs when you stand or sit for hours, and that pressure pushes more fluid into your ankles and feet. Heat widens the blood vessels near your skin to release warmth, so more fluid escapes into the tissues around them. **Your lymphatic system sets how fast the extra drains away.** It has no heart of its own. Lymph moves when the muscles around your lymph vessels squeeze them, which is why a walk drains swollen ankles, and when your diaphragm moves up and down as you breathe deeply. When you sit still and breathe shallowly for hours, lymph flow slows down. ## Common Causes of Fluid Retention Most fluid retention comes from everyday habits and normal changes in your body. The most common causes are: - **Sitting or standing still:** long desk days, flights and car journeys. - **Salt:** most of the salt you eat is already in bread, cheese, cured meats, soups, sauces, ready meals and takeaways. - **Heat:** hot weather, hot baths and saunas. - **Hormones:** the days before your period, pregnancy and the years around menopause. - **Medicines:** some blood pressure tablets, the contraceptive pill, hormone therapy, some antidepressants, steroids and anti-inflammatory painkillers such as ibuprofen. - **Extra weight:** carrying more weight raises the pressure in the veins of your legs. - **Low protein in your blood:** a protein called albumin helps hold water inside your blood vessels, and levels can fall with liver or kidney disease or a very poor diet. Less often, swelling comes from problems with your heart, kidneys or liver, a blood clot or an infection. The section on when to see a GP, below, explains the signs. ## Where Fluid Retention Settles Fluid does not collect evenly. Where it settles depends on gravity, the thickness of your skin, how much you move each part of your body and what your hormones are doing. Each pattern has its own cause and responds to its own mix of movement, nourishment and calm for your nervous system. ### Legs, Ankles and Feet Gravity pulls fluid down, so your ankles and feet are the first place most people notice it, often by the evening and after a long flight. Your calf muscles act as a pump: every time they tighten, they squeeze blood and lymph back up towards your heart. When you sit still, the pump stops working. A short walk or ten calf raises switches it back on. ### Face and Eyes When you lie flat overnight, gravity no longer pulls fluid towards your feet, so some of it spreads into your face. The skin around your eyes is among the thinnest on your body, so a small amount of fluid shows there first. A salty dinner, a late drink or sleeping face down makes it worse, and the puffiness usually drains within an hour or two of getting up. Keeping salty food for lunch rather than dinner makes a visible difference. ### Belly A swollen belly can be fluid, gas or both. Fluid retention tends to make your middle feel soft and heavy, with your waistband growing tighter through the day, while gas bloating usually comes and goes with meals and can feel tight and hard. Your diaphragm helps move lymph out of your abdomen each time you breathe deeply, so shallow, stressed breathing slows that drainage. ### Hands and Fingers Your hands swell most in hot weather, on long flights and after hours at a keyboard with your arms held still. Rings that will not come off and stiff fingers in the morning are the usual signs. ### Breasts In the week or so before your period, changes in oestrogen and progesterone make breast tissue hold more fluid, and your breasts can feel full, heavy and tender. The tenderness usually eases once your period starts. ### The Whole Body Around Menopause As oestrogen rises and falls unpredictably in the years around menopause, many women notice puffiness that moves around the body: swollen fingers one week and a heavy middle the next. Hormone therapy can add to it in the first few months. ## When Swelling Needs a GP Most fluid retention is mild and goes down within a day or two. NHS guidance asks you to see a GP if swelling has not improved after a few days of looking after it at home, if it gets worse, or if you have diabetes and your feet, ankles or legs swell. Ask for an urgent GP appointment or call NHS 111 if: - one leg, ankle or foot swells and there is no obvious cause, such as an injury - the swelling is severe, painful or starts very suddenly - the swollen area is red or feels hot to the touch - you also have swelling in your face, tummy or other parts of your body - you have a high temperature or feel hot, cold or shivery - you have a condition that affects your heart, kidneys or leg veins Call 999 if you feel short of breath, your chest feels tight, heavy or painful, or you cough up blood. Swelling in one leg together with any of these symptoms can mean a blood clot has travelled to your lungs, which needs treatment in hospital straight away. ## Simple Ways to Start Reducing Fluid Retention This Week You can start with five small changes. Each one works on more than one of the systems above. **Get up every 30 to 45 minutes.** Stand, walk to the window and rise onto your toes ten times. Each rise squeezes your calf muscles and pushes fluid out of your lower legs. **Raise your legs for 15 minutes in the evening.** Lie on the sofa or the floor with your feet on cushions above the level of your hips, and let gravity carry fluid back towards your heart. **Keep drinking water.** Drinking less does not reduce fluid retention. When you are short of water, your brain releases more antidiuretic hormone and your kidneys hold on to what you already have. Our guide to [the best times to drink water](https://richhealthmagazine.com/article/optimal-water-intake-the-most-effective-times-to-hydrate-your-body) helps you spread it through the day. **Read the salt on three labels.** Check your usual bread, your favourite sauce and one ready meal or takeaway. Swapping just one of them for a lower-salt version cuts the amount of water your kidneys need to hold. **Take five slow breaths into your belly before bed.** Let your stomach rise as you breathe in and fall as you breathe out. Deep breathing moves your diaphragm, which helps drain lymph from your abdomen, and it calms the stress hormones that tell your kidneys to keep salt. Our guide to [calming your nervous system in minutes](https://richhealthmagazine.com/article/how-to-calm-your-nervous-system-7-fast-techniques) gives you more techniques. Tonight, before you go to bed, take your first readings. Press your thumb into the skin over your shin for five seconds and see whether it leaves a dent. Look at the marks your socks have left around your ankles, and check whether your rings still turn as easily as they did this morning. Tomorrow, look at your face in the mirror as soon as you wake and weigh yourself before breakfast. Those few minutes give you the start of your own fluid map: a clear picture of where your body holds on to water, and the first step towards letting it go. ## In Case You Were Wondering **Q: Why do my ankles and feet swell?** Ankles and feet swell when fluid builds up in the tissues, a condition called oedema. Gravity pulls fluid towards the lowest part of the body, so long periods of sitting or standing, hot weather, salty food, pregnancy, extra weight and some medicines commonly cause it. The swelling usually goes down with gentle walking and by raising the legs above hip level. A GP should check swelling that lasts more than a few days, affects only one leg, or is painful, red or hot. Swelling together with shortness of breath or chest pain needs a 999 call. **Q: Why does my face look puffy in the morning?** Lying flat overnight lets fluid spread through the body instead of collecting in the legs, and some of it settles in the face. The skin around the eyes is very thin, so small amounts of fluid show there first. Salty or late meals, alcohol, poor sleep and sleeping face down can all make it worse. Morning puffiness usually fades within an hour or two of getting up. Puffiness that lasts all day or comes with swelling elsewhere in the body should be checked by a GP. **Q: Why does heat make you retain water?** In hot weather, the blood vessels near the skin widen to release heat. Wider vessels let more fluid seep into the surrounding tissues, and gravity pulls it towards the hands, feet and ankles. Losing water through sweat also leads the body to release hormones that hold on to salt and water. Heat swelling usually eases in cooler conditions, with gentle movement and by raising the swollen area. **Q: Why do my breasts swell before my period?** Changes in oestrogen and progesterone in the second half of the menstrual cycle make breast tissue and milk ducts grow slightly and hold more fluid. Breasts can feel full, heavy, lumpy and tender, usually in the week before a period, and the feeling eases once the period starts. A new lump, pain in one specific spot or any change that does not follow the monthly cycle should be checked by a GP. --- *This article is for general information only and is not medical advice. It does not replace a diagnosis or treatment from your GP or another qualified health professional. Speak to your GP or pharmacist before you change your diet, exercise routine or medicines, especially if you are pregnant, have a long-term health condition or take regular medication. If you have sudden, severe or one-sided swelling, or swelling with shortness of breath or chest pain, call 999.*