What do Compression Socks Do, According to Doctors

9 Min Read

Compression socks apply pressure to the leg below the knee. They improve blood circulation, support leg muscles, and normalize blood pressure. They’re indicated for conditions like varicose veins, spider veins, and blood clots.

As a sports doctor, I prescribe compression socks often. In this article, I’ve compiled everything I know about them.

Read on to learn what compression socks do, how they differ by type and class, and more.

Disclaimer: This guide was created for educational purposes. It neither offers nor replaces medical advice. Learn more here.

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Table of Contents

What Do Compression Socks Do?

Compression socks are a form of compression therapy. They apply pressure to the foot and lower leg.

They help treat swelling, discomfort, and medical conditions like varicose veins. They have no known side effects and are useful to patients of all ages, including young adults.

There are two types of medical socks. The first is the uniform compression sock, which applies the same amount of pressure all over. The second – the graduated compression sock – applies the most pressure around the ankle and less up the leg.

Uniform and graduated compression socks both have their own advantages.

Your doctor will help you choose the one that’s right for you:

  1. Compression socks for medical patients: Compression socks help patients with spider veins, blood clots, and other venous conditions. They are also effective at reducing swelling and improving blood circulation.
  2. Compression socks for healthy adults: Compression socks are useful to healthy adults, especially ones with sedentary lifestyles. Doctors, pilots, drivers, office workers, and others can all benefit from wearing them. Also, they are ideal for warehouse workers and people who are always on their feet.

How Do Compression Socks Work?

Many medical conditions weaken the veins. When this happens, blood circulation breaks down. This causes many problems, from swelling to permanently enlarged veins. It can also result in a painful, problematic blood clot.

This is where compression socks come in. They apply pressure to our legs and feet. This “squeezes” the blood there towards the heart, normalizing our circulation.


  • Stops blood from pooling in our feet and legs.
  • Saves veins from becoming overworked.
  • Decreases internal vein pressure by providing external pressure.
  • Slows the formation of new varicose veins.

That, in a nutshell, is how compression socks work. They apply pressure, normalizing circulation and fixing all kinds of venous problems.

Note: Athletic compression socks have a different mechanism of action. They aren’t medical compression socks and don’t offer the benefits described above.

What Do Compression Socks Do for Swelling?

Swelling in the legs and feet is often caused by poor blood circulation. Since compression socks improve blood flow, they can also reduce swelling. It doesn’t matter if the underlying reason is a venous condition or a sedentary lifestyle.

If you wear compression socks for swelling, it’s best to start early in the morning. Your legs and veins aren’t swollen yet, so putting them on will be easier. I recommend applying them while still in bed.

Will my socks work if I put them on later in the day?

For sure! If you didn’t start wearing them in the morning, feel free to do so later on. They may be harder to put on – especially if they’re a high compression grade – but they’re still effective.

Tip: If your legs are swollen, place them above your body’s midline for 5-10 minutes. You can do so by lying down or sitting with your feet above your waist. This will reduce the swelling and make it easy for you to put your socks on.

Tip: If you find it hard to get your socks on, even in the morning, talk to your doctor. Devices that help put on compression products are available.

Tip: Compression socks are also suitable for people who experience toe numbness. The reason for this is that toe numbness can happen due to poor circulation, which compression socks help alleviate.

What Do Compression Socks Do for Runners?

Running stresses the legs and feet. This often causes reduced blood flow and swelling. This is partly why running shoes tend to run a size big; they need to accommodate that swelling!

As you may have guessed, this isn’t optimal for sports performance. Swollen feet, toes, and legs have less power, flexibility, and ease of movement. They are also less mobile, which makes it easier to, for example, sprain an ankle.

Compression socks help fix this. They improve blood circulation, driving blood and oxygen to the feet. This reduces lactic acid buildup, prevents excessive swelling, and reduces foot stress.

Specific sports performance and recovery benefits include:

  • Improved athletic performance
  • Faster muscle recovery
  • Improved oxygen flow
  • Reduced muscular tension
  • Injury prevention
  • Reduced muscle cramps
  • Reduced muscle soreness
  • Faster body cooling

I want to highlight the ‘injury prevention’ point. Compression socks improve blood flow, reducing muscular tension and increasing flexibility. This reduces the likelihood of cramps, sprains, tears, etc.

So even though some people still think compression socks are only for older people, they can also make you a better, more powerful athlete.

What Do Compression Socks Do for Other Athletes?

Medical compression socks can help athletes stay warm, perform better, and recover faster.

Non-medical, sports-specific compression socks can improve joint stability. Let’s go over all these benefits in detail.

Medical Compression Socks

  1. Compression socks help us stay warm. They do this by driving cold blood out of our legs and feet. This is why most good ski and snowboard socks have some compression to them.
  2. Compression socks increase blood circulation and oxygen flow, improving muscular performance. This can improve strength, endurance, and flexibility.
  3. Compression socks improve sports recovery. They do this by shuttling blood and nutrients to our legs and feet.

Sports Compression Socks

Like medical compression socks, sports compression socks can improve circulation. They also stabilize our joints and soft tissues, helping us perform better.

The caveat is, this requires sports-specific, high-compression socks. If you wear them, remove them after an hour or two for your own safety.

What Do Different Compression Classes Do?

A compression sock’s ‘class’ or ‘grade’ refers to how much pressure it applies to the foot. It’s usually displayed in mmHg, or ‘mercury millimetre high’.

Some socks apply more pressure; others apply less. We’ll explain how the different pressure classes are different below.

Note: These four compression classes are true according to the RAL-GZ 387 standard. Other standards may have different compression classes.

Compression Class 1 (18-22 mmHg)

This compression class offers light compression.

It’s perfect for people with symptoms like:

  • Enlarged veins
  • Visible spider veins
  • Sensations of hot, cold, or pain in the feet and legs
  • Painful leg muscles, especially after sitting or standing
  • Swollen feet and ankles in the evening.

This compression class is also indicated for prophylactic and general usage. It can benefit pregnant women, those who work standing up, and mostly-sedentary individuals.

In most countries, you can buy a Class 1 compression garment over-the-counter, i.e. without a doctor’s prescription.

Compression Class 2 (23-32 mmHg)

This class offers moderate compression.

It is indicated for the following symptoms and cases:

  • Painful leg muscles, especially after sitting or standing
  • Multiple visible spider veins
  • Multiple dilated, gnarled, or enlarged veins
  • Varicose veins
  • Night-time leg cramps
  • Chronically swollen feet and ankles
  • Post-surgery

You almost always need a physician to prescribe you Class 2 products. Wearing compression socks like these without seeing a doctor can be dangerous.

Compression Class 3 (34-46 mmHg)

Compression Class 3 offers moderate-to-high compression.

It can help with:

  • Thrombotic disease recovery
  • Severe varicose veins
  • Leg vein surgery recovery
  • Leg swelling and obvious trophic symptoms
  • Deep vein thrombosis
  • Lymphatic and venous insufficiency

Don’t buy or wear Class 3 products without a doctor’s visit.

Compression Class 4 (49 mmHg+)

This is the highest compression class available.

It is indicated for:

  • Lymphedema
  • Burns

The level of compression is highest at Class 4. Garments should be prescribed by a phlebologist.

Compression Class “A” (Non-Medical)

There’s a fifth, non-medical class of compression. It’s usually sold over the counter, offering about 10-14 mmHg of pressure. It’s safe for most people to use without a doctor’s consultation. It’s sometimes called “Class A Compression.”

Class A is useful for long flights, long drives, and other times the feet can use a little extra circulation.

What do Different Compression Sock Types Do?

Compression socks don’t just have different compression grades. They also have different intended uses. Here are the 5 most common ones, listed below.

1 – Therapeutic and Prophylactic Socks

Therapeutic and prophylactic socks treat and prevent light conditions.

They’re indicated for people who:

  • Have a genetic predisposition to a vein disease
  • Are at risk for blood clots
  • Spend extended periods of time sitting and standing
  • Suffer from constipation

These usually apply Class 1 Compression. This makes them imperceptible to the wearer but therapeutically effective.

2 – Venous Insufficiency Socks

This kind of sock is made to address venous insufficiency and improve blood flow. Most venous insufficiency socks are also Class 1, though some are Class 2.

3 – Socks for Healing Trophic Ulcers

Doctors use these socks to treat and heal leg ulcers. The compression class is usually 2 or 3, as the level of pressure required is high.

4 – Sports Socks

These socks stabilize joints, reducing the load on joints and ligaments. They also improve blood circulation during exercise. The level of compression on these varies greatly depending on the individual and the sport.

5 – Travel Socks

These are worn on flights to reduce the risk of thrombosis. The compression level can vary but usually, we’re talking about Class 1 and Class 2.

What’s the Right Way to Wear Compression Socks?

For compression socks to work as intended, they need to be put on the right way. They should be uniform on your foot and leg, with no bundling, bunching, or loose areas.

Now, how do you actually put compression socks on the right way? This can be tricky, given they’re so tight and delicate. Putting them on without tearing or stretching them is an effort.

To wear your compression product the right way, follow the following steps:

  1. Turn your compression stocking or sock inside out above the ankle. Leave the ankle outside in.
  2. Take the part of the sock you didn’t turn inside out. Insert your foot. Carefully flatten the fabric so the foot is comfortably in the sock.
  3. Slowly release the rest of the sock or stocking upwards, stretching it over your leg. Be gentle; you don’t want to rip the garment.
  4. Level the compression socks from ankle to knee. Straighten folds if they appear.


  • Be patient with your compression hosiery. This is doubly true for those using garments with high compression levels. The more pressure your product applies, the more care you need to take.
  • Be mindful of how long you wear compression socks, because if you wear them too long, you may experience side effects.
  • There are special devices for putting compression garments on. If you have difficulty wearing yours, you may want to buy one. In my own practice, I ask all patients wearing 3rd- and 4th-grade compression products to use these.
  • The method above is suitable for most patients. However, there are other methods for specific conditions and products. For example, if you have varicose veins, you may want to ask your doctor about the best way to apply them.


Dr. Karim Maghreby

Proofread by:

Dr. Holly Hanson

Last Updated:

June 28, 2022


Dr. Maghraby is a medical doctor and published physician scientist. He’s an avid runner and a user of sports compression gear.


Dr. Hanson is a doctor of physical therapy. She’s a practicing PT and clinic supervisor with 8 years’ experience.