You may have heard of compression socks or even have a family member that uses them to address circulation problems caused by a medical condition. Some runners and ballplayers love them as a means to support veins in hardworking ankles and calves as they circulate blood back to the heart, so the heart can pump blood back through the lungs to pick up more oxygen. This beginner’s guide to compression socks will help you understand the variety and uses of this type of legwear.

Compression Socks Help Defy Gravity

Gravity affects everything on the planet, including the body’s circulatory system. Standing for prolonged periods of time, sitting cramped up in an airplane seat for hours, and certain diseases all cause blood to pool in the lower extremities, particularly around the ankles. Our hearts pump blood throughout the body via arteries to get oxygen from the lungs to the cells that need it. Arteries branch out all over the body, getting smaller as they get further from the heart. Eventually they connect with capillaries—tiny, thin-walled blood vessels that allow nutrients, oxygen, and waste to pass to and from our tissues. The capillaries exchange oxygen, which travels to the cells that need it, for carbon dioxide, which travels out of tissues back into the capillaries. Veins then carry the deoxygenated blood back toward the heart, so the heart can pump it through the lungs to get rid of the carbon dioxide and refresh the blood with oxygen.

Sometimes, however, a medical condition makes it harder for veins to do their job of sending blood back toward the heart. Veins are supposed to accomplish this through the movement of muscle in the blood vessel’s walls, and by pressure from surrounding skeletal muscles as we move about. Veins have special valves in them to prevent “backflow” and fight the pull of gravity as the blood moves back up toward the heart.

With some medical conditions, veins and the valves in them weaken, and they can’t fight the force of gravity as effectively as they once could. When this happens, blood tends to pool, causing swelling and discomfort, particularly around the ankles. Diabetes, varicose veins, deep vein thrombosis, and pregnancy can all cause this kind of swelling. Under these conditions, doctors may prescribe compression socks to aid circulation and prevent blood clots.

Compression socks help defy gravity by exerting pressure—literally squeezing—around the ankles, gradually decreasing the pressure as the sock reaches up toward the knees. The socks give an assist to muscles and faulty valves in the veins, helping them push blood back upward toward the heart.

Some types of compression garments are just for bedridden people, whose bodies temporarily can’t participate in moving blood back toward the heart. These kinds of compression garments may exert the same amount of “squeeze” through their entire length. Compression “sleeves” have openings at both ends, for wearing on the arms, or on legs under certain conditions such as bed rest or limited mobility following surgery.

Even healthy people are at risk of swollen ankles and legs or even blood clots forming, in places or at times that limit standing up and moving around, such as long airplane flights. Compression socks can help prevent blood clots under these circumstances. It’s no small matter to keep moving and keep blood flowing because clots that form in the legs can create a dangerous and life-threatening condition called “deep vein thrombosis” or DVT for short. DVT causes redness, swelling and clots that can break free and travel to the lungs, where they could cause a pulmonary embolism—a life-threatening blockage of blood flow in the lungs.

Nurses, flight attendants, retail workers, and anyone else who spends a lot of time on their feet each day might benefit from the right kind of compression socks. These socks reduce swelling, pain, and fatigue from long periods of standing.

Why Athletes Use Compression Socks

Athletes like runners and ballplayers love compression socks. These socks reduce muscle fatigue and soreness and can help in recovery from injury. By their nature, compression socks improve blood circulation. Tough workouts, marathon runs, or intense competitive games where athletes use their muscles without rest for prolonged periods, deplete oxygen from the cells faster than the blood circulation can replace it. When this happens, the body produces lactates, to use as energy. A buildup of lactates causes muscle soreness. Keeping the blood flowing efficiently back to the heart, so the heart can pump it back to the lungs for an oxygen refill, helps fend off this kind of soreness. MK Socks offers compression socks made for baseball, basketball, running, and more.

Choosing the Right Compression Socks

First, talk to your doctor and get the go-ahead to use compression socks. They’re not for everyone, but if your physician agrees they can relieve leg discomfort, help avoid or recover from injury, or support athletic performance, you’ll need to know how to choose the right compression socks.

These socks come in various types that exert different amounts of pressure on the legs. Mild compression consists of 15-20 mmHg (millimeters of mercury, or the amount of pressure a one-millimeter column of mercury exerts at 0°C) and is best for problems like varicose veins, fatigue, and minor swelling. The next level is 20-30 mmHg, for more severe varicose vein conditions or lymphatic edema, a condition where the lymph nodes are damaged or missing and lymphatic fluid builds up in the legs. The highest-pressure versions, 30-40 mmHg, are for leg ulcers or “post-thrombotic syndrome,” a chronic condition that develops after an episode of DVT and involves redness, swelling, and prolonged or permanent weakness in the veins. Your ankle and calf measurements also determine the socks you need. Consult your doctor or retailer to determine the correct size.

This beginner’s guide to compression socks will give you a start in deciding whether compression socks are right for you. If you prefer socks that are just for fun, take a look at our WWE socks collections, or if you want to support your favorite team, design your own custom socks with team colors.