Swollen Legs: Main Causes and Treatment

Swollen legs are one of the symptoms of fluid retention. This retention may be due to bad life habits or an underlying condition.
Swollen Legs: Main Causes and Treatment

Last update: 19 November, 2019

Swollen legs due to fluid retention are a very frequent problem among the general population, whether they’re athletes or not. Even though fluid retention in itself is a frequent condition, it’s usually associated with bad dietary habits or a lack of physical activity.

In some cases, we can experience this retention in our legs, especially the ankles and knees. In this article, we’ll take a look at why we should pay closer attention to swollen legs. We’ll also learn about the causes and possible treatments.

The physiology of fluid retention

To understand the causes of why liquid may accumulate in the legs, we must understand how this accumulation happens. The heart is a pump that’s constantly sending blood to the vascular tree. It travels through the whole body to bring oxygen and the nutrients we need.

When blood leaves the heart through the main arteries, they have a thick wall that allows them to carry it at great pressure. However, when the blood goes through the capillaries and reaches the venous territory, it meets blood vessels with small contractile capacity. And they also have to carry the blood back to the heart going against gravity (except for the brain).

If there’s too much liquid circulating due to the inefficiency of the heart or the venous system, the liquid will accumulate in the veins. When there’s an accumulation of liquid in a blood vessel, the body takes a part of that liquid and transports it to the tissues so that there’s no cardiovascular overload. When this happens in the legs, they become swollen due to fluid retention. This phenomenon is known as edema.

Causes for swollen legs

Now that we understand how liquid accumulates in the legs, we can list the possible causes for this:

  • A failure in the cardiovascular system may produce fluid retention, which would be more noticeable in the lower extremities because liquid tends to accumulate there more easily due to gravity. Cardiac insufficiency in the right cavities of the heart causes blood to accumulate in the venous system, which is why the body will expel the liquid towards the tissues.
A woman with swollen legs sitting on the bed
  • Venous insufficiency (thrombosis) or lymphatic system failure will also manifest as fluid retention or edema in the legs. This is because the lymphatic system is in charge of collecting the accumulated liquid and bringing it back to the bloodstream. Varicose veins are a sign of bad circulation in the legs, and this built up liquid will go to the tissues and cause swollen legs.
  • When there are few proteins in the blood, the body interprets it as too much fluid in the circulation and expels some of it to the tissues. Illnesses that cause a loss of protein may also cause fluid retention. This is the case of some liver and kidney illnesses, such as nephrotic syndrome.
  • Kidney failure is the kidney’s inability to filter the liquids in our body correctly. This may also cause fluid retention.
  • Other non-pathological causes may be simple bad habits. A sedentary lifestyle, a diet that’s too high in salt, or processed food are examples of possible causes to retain fluids.

We must keep in mind that most of the causes we listed are pathologies. This means they’re also more frequent in older people due to an organ or system failure. In young people, fluid retention is usually due to bad habits, and it’s easy to fix in principle.

Treatment for swollen legs

The treatment will be aimed at making us lose liquid. This way, the accumulated liquid in the leg tissues will return into the circulation. Let’s list some of the ways that we can combat this problem:

  • It’s very important to practice physical exercise. This is because our body uses the liquid in the metabolism of some macronutrients, and to cool down when we perform intense activities.
A woman running outside to reduce swollen legs
  • If we suffer from a cardiovascular illness, it’s essential to reduce our salt intake to the minimum. Salt increases blood pressure and attracts water by osmosis. Therefore, it’ll cause us to retain fluids.
  • Following a balanced diet and consuming natural foods. We must avoid processed foods with a high salt content.
  • Drink plenty of water. This way, we’ll assist the filtration of liquid through our kidneys.
  • If you still haven’t been able to reduce the swelling, and your kidneys are in good condition, you can ask a doctor for a dietary supplement with diuretic properties. Horsetail is a great example.

If none of this is effective because there’s an underlying pathology, we’ll have to look even further. We may need to take a diuretic medication such as furosemide, but always under the advice and supervision of a specialized doctor.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Causes and signs of edema – InformedHealth.org – NCBI Bookshelf [Internet]. [cited 2019 Oct 23]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK279409/
  • Gorman w. P, Davis KR, Donnelly R. Swollen lower limb—1: General assessment and deep vein thrombosis. BMJ. 2000 May 27;320(7247):1453–6.
  • Wright NB, Carty HML. The swollen leg and primary lymphoedema. Arch Dis Child. 1994;71(1):44–9.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.