Compression levels and indications

Basically, the greater the compression level, or compression strength, the tighter the compression stocking. These levels are measured in millimeters of mercury (mmHg). It's the same scale used to take your blood pressure.

Compression levels and indications

The most beneficial compression socks are “graduated” as opposed to “uniform” in strength. Graduated compression socks are tighter at the ankle than they are at the top. The graduation helps push blood back up toward the heart, aiding in circulation. 

Compression stockings with relatively low compression levels can be purchased without a prescription at drugstores, medical supply stores, and online.

These over-the-counter items usually come in compression levels of around 15-20 mmHg.

Compression stockings with higher levels of compression are prescribed by doctors. The prescription will include the specific strength you need. By law, no prescription is required, but most pharmacies won’t dispense higher-level compression wear without a prescription.

By “high-level compression,” we mean those that generally range from 20-30 mmHg to 30-40 mmHg; while these strengths are generally safe to wear, certain individuals may be at risk of harm due to contraindications, so the oversight of a doctor is always recommended. Compression levels in even higher ranges do exist, but your doctor should tell you about those.

A trained and certified fitter will need to take measurements to ensure you get the correct level of compression and size. If your doctor or physical therapist can’t do the fitting, they should be able to refer you to someone who can. 

Compression levels explained

For what medical problems are the different compression levels used? A broad overview is provided below.

These are general guidelines. The severity of a problem helps to determine the level required.

As mentioned above, you should consult your doctor regarding the compression level appropriate for you.

Compression level 1

18–21 mmHg

  • Mildly painful, heavy and tired legs
  • Support and comfort when standing or sitting for long periods
  • Support for general health and energy
  • For improved circulation, especially in the legs
  • Additional support on active days when you work hard or take a trip
  • These products may help during pregnancy to prevent varicose veins and reticular veins

Compression level 2

23–32 mmHg

the most frequent compression level prescribed by doctors

  • For varicose veins with mild tendency to oedema
  • For varicose veins during pregnancy
  • After a varicose vein treatment with surgery such as sclerotherapy and phlebectomy
  • For the treatment of orthostatic/postural hypotension, a form of low blood pressure
  • For deep vein thrombosis
  • For post-thrombotic syndrome
  • For healed leg ulcers

Compression level 3

34–46 mmHg

  • For moderate venous oedema and lymphoedema
  • For lipoedema
  • Used after broken bones and orthopaedic operations
  • Used for the treatment of skin changes with healed ulcers

Compression level 4

at least 49 mmHg

  • For severe lymphoedema
  • For pronounced post-thrombotic syndrome

When should I consider wearing compression stockings and consult a doctor?

  • Pregnancy
  • Chronically swollen, painful or tired legs
  • Poor circulation in the legs
  • Varicose veins or venous leg ulcers
  • A known risk of blood clots, especially in the legs
  • History or family history of deep vein thrombosis
  • Long confinement to bed, for example after an operation
  • Prevention: It makes good sense to wear compression stockings to fix a small problem before it becomes a big one.

When is caution required with compression stockings?

  • Arterial insufficiency, intermittent claudication, ischaemia
  • Uncontrolled congestive heart failure (CHF)
  • Acute dermatitis, weeping dermatosis, cutaneous sepsis
  • Signs of an infection in the legs

There may also be other reasons. Make sure that your doctor is aware of your medical history before they prescribe compression stockings.

What is the difference between compression stockings and support stockings?

The term “support stockings” is widely known and often also used for medical compression wear. The principles of the two types of stockings are different, though.

Support stockings exert passive resistance to swelling, while compression stockings apply active pressure on the veins of the leg. This prevents them from dilating and facilitates venous return.

Medical compression garments are produced under strict medical and technical specifications to guarantee adequate ankle pressure and graduated compression along the leg. 

Further reading

What is compression therapy?

What is compression therapy?

Medical compression therapy applies a type of elastic device on limbs or other body parts to exert a controlled pressure on them. Thereby, the device squeezes the vein walls together and improves the circulatory rate. Medical compression also helps with reduction of edema and recreates conditions beneficial for the healing of chronic inflammatory disorders.
CEAP classification for chronic venous disorders

CEAP classification for chronic venous disorders

Chronic Venous Disorders (CVD) is a collective term that describes a long-standing condition involving impaired venous return in varying degrees of severity. To distinguish the different manifestations of CVD, the CEAP classification system is used.
Chronic venous disorders (CVD)

Chronic venous disorders (CVD)

Constant standing or sitting impedes the flow of blood towards the heart. Under certain circumstances, this can lead to venous insufficiency, which is characterized by improperly functioning vein valves that interfere with venous return and cause the blood to pool in the veins. If left untreated, venous insufficiency can result in the formation of serious disorders, including phlebitis, pulmonary embolism, or ulcers.
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