Water retention is possible when pressure inside capillaries (blood vessels) changes.
A complex system of hormones and prostaglandins (hormone-like substances) are used by the human body to regulate water levels. This means that excess water can be excreted quickly from the kidneys in the form of urine. Likewise, if we drink less fluid, there will be less urine produced.
Water retention can occur in many different areas of the body and for different reasons. We will look at these individually.
- Up to 70 percent of our body is water.
- Muscle is made up of approximately 75 percent water.
- Fat consists of about 50 percent water.
- Bones are made up of about 50 percent water.
Causes of water retentionThere are many possible causes of water retention, including the following:
Fluid rich in nutrients, vitamins, and oxygen continuously passes from tiny blood vessels (capillaries) into surrounding tissues - this fluid is known as interstitial fluid.
Interstitial fluid nourishes cells and eventually makes its way back to the capillaries. Water retention may occur if the pressure inside the capillaries changes.
Water retention is also possible if something occurs that makes the capillary walls too leaky. If something goes wrong with pressure or the wall becomes too leaky, excess liquid will be released into the spaces between cells.
If too much fluid is released, more of it will remain in the tissues, rather than returning to the capillaries, resulting in swelling and water retention.
The lymphatic system
The lymphatic system drains fluid from tissues (called lymph) and empties it back into the bloodstream. However, if too much fluid is released in the first place, the lymphatic system can be overwhelmed - it is unable to return fluid fast enough, and it accumulates around the tissues.
Sometimes, if the lymphatic system is congested, the rate at which fluid is returned to the bloodstream may change. This means that fluid might remain in the tissues, causing swelling in various parts of the body, including the abdomen, ankles, legs, and feet.
Normal pressure within blood vessels is partly maintained by the pumping force of the heart. However, if the heart starts to fail, there will be a change in blood pressure, which often results in serious water retention.
Typically, the legs, feet, and ankles will swell. Fluid will also build up in the lungs, giving the patient a long-term cough and/or difficulty breathing.
Congestive heart failure can eventually cause breathing problems, as well as excessive stress on the heart. The patient will probably be prescribed diuretics. A diuretic is anything that promotes the formation of urine by the kidney - in other words, anything that helps the body shed water.
Blood is filtered in the kidneys - waste, fluids, and other substances are extracted and cross into tiny tubules; from there, the bloodstream reabsorbs anything the body can reuse. What the body cannot reuse - waste - is excreted in urine.
In most cases, kidneys can eliminate all waste materials that the body produces. However, if the blood flow to the kidneys is affected, problems can occur. For instance, in kidney failure, waste material, including fluids, cannot be eliminated from the body properly, resulting in fluid retention.
The weight of the uterus on the major veins of the pelvis can cause a build-up of fluid in the body during pregnancy. In most cases, it is nothing to worry about and generally resolves after the baby is born.
Physical inactivity can sometimes cause water retention.
Exercise helps the leg veins return blood to the heart. If the blood does not travel fast enough, it will begin to accumulate in the legs, resulting in higher pressure in the capillaries. Fluid will leave the capillaries at a higher rate because of the higher pressure.
The higher pressure also makes it harder for fluids to come back later on.
Exercise is necessary to stimulate the lymphatic system to carry out its function of regulating overflow - bringing fluids back into the bloodstream at rates that may regulate body water levels. Very long periods of physical inactivity, such as a long-haul flight, increase the risk of water retention.
During a long-haul flight, even minor physical movements, such as standing up on tiptoes a few times, rotating the ankles, and wiggling the toes can help reduce fluid retention.
Humans require a certain level of proteins for effective water balance. An individual with severe protein deficiency may find it harder to get the water from the tissue spaces back into the capillaries. The enlarged abdomen of someone who is starving is mainly caused by a lack of protein in their diet.
When inflammation is present in the body, histamine is released. Histamine causes the gaps between the cells of the capillary walls to widen, making them leakier. The aim is to make it easier for infection-fighting white blood cells to quickly get to the site of an inflammation. However, if the inflammation persists for a long time, water retention can become a problem.
Medication caused water retention
Some medications can cause water retention, including:
- Estrogen-containing drugs, such as the combined oral contraceptive pill, or HRT (hormone replacement therapy).
- NSAIDs (non-steroidal anti-inflammatory drugs) - medications with pain-reducing, fever-reducing effects. In high doses, they are actually effective in reducing inflammation. Examples include aspirin, ibuprofen, and naproxen.
- Beta-blockers - used to treat abnormal heart rhythms and prevent tachycardias.
Pre-menstrual water retention
Pre-menstrual water retention can cause bloating and breast tenderness. Experts say this is due to hormone imbalances and some nutritional factors:
- Malnutrition and bad diet - a poor diet low in protein result in low levels of albumin, which may also play a part in developing water retention.
- Salt (sodium) - sodium-rich foods may cause water retention.
- Allergies - some foods and insect bites may cause edema in susceptible people.
- Thyroid disease - people with a disorder of the thyroid gland commonly experience water retention.
Treatments for water (fluid) retention
Treatment for water retention depends on several factors, including the root cause.
Treatment for leaky capillaries
In this case, tissues are retaining both water and protein. Diuretics would cause the kidneys to remove fluid faster from blood, while protein in the tissue spaces would continue drawing fluid from blood into tissues - resulting in dehydration of the blood. Eventually diuretics can actually make water retention worse.
A doctor will treat the cause of the leaky capillaries. As they are often linked to a protein problem, medications will be given that help break up the protein in the tissue space.
It can be difficult for a doctor to distinguish between leaky capillaries and non-leaky capillaries water retention.
Reducing water retention symptoms
The following remedies may reduce the symptoms of water retention:
- Reduced salt consumption.
- Weight reduction.
- Regular exercise.
- Raising the legs several times per day to improve circulation.
- Wearing supporting stockings if the water retention occurs in the lower limbs.
- Avoiding sitting and standing still for too long.
- Walking regularly when traveling by car, train, boat, or plane.
- Avoiding extremes of temperature, such as hot baths, showers, and saunas. Dressing warmly if it is cold.
- Massage - if the affected area is stroked firmly in the direction of the heart, it may help move the fluid. It is important that the hand movements do not cause pain.