If you have looked for compression stockings or socks, you will have seen that they all promise to squeeze. Squeezing the leg is easy. What helps circulation is squeezing in the right order: more at the ankle and less towards the knee. That is graduated compression, and here we explain how it works and why tighter is not always better.
The job of these garments is to help blood circulate better through the legs. That way they help ease the feeling of swelling in the legs, which you notice above all in the last hours of the day.
Why do legs swell?
The circulatory system is made up of the heart, the arteries and the veins. The arteries carry blood from the heart to the rest of the body, and the veins bring it back from the rest of the body to the heart, closing the circuit.
Inside the veins there are small valves that keep blood flowing in one direction. In the legs, that uphill journey gets help from two pumps: the sole of the foot and the calf, which squeeze the veins as you move and push the blood upwards. When that push falls short, for example after many hours standing or sitting, gravity gains ground and some fluid builds up in the tissues (oedema).
What socks for swollen legs do is give those two pumps a hand, so blood climbs back to the heart more easily (what is called venous return). What they are useful for in each situation, and what the studies say, is in what compression socks do.
How much pressure do compression socks exert?
The pressure of these garments is measured in millimetres of mercury (mmHg), the same unit as blood pressure. In Spain, the usual scale for therapeutic compression is this1:
- Light: between 18 and 21 mmHg
- Normal: between 22 and 29 mmHg
- Strong: between 30 and 40 mmHg
- Very strong: over 40 mmHg
From normal compression upwards, it is always used on the advice of a health professional. Below this scale sits the everyday wellbeing range: the socks you put on to work, travel or spend the day on your feet, with no prescription or appointment needed. What each number means, and why the same figure feels different depending on the moment, is explained in what mmHg means in compression stockings.
Why graduated compression matters
When we talk about graduated compression we mean that the sock applies more pressure at the ankle and less around the calf. It is graduated because the pressure goes down as the garment rises towards the knee.
Think of a tube of toothpaste. If you squeeze it from the bottom, the paste moves up towards the opening. If you squeeze it in the middle, some goes up and some goes back down. Something similar happens with the blood in your legs: if the garment squeezes harder higher up than lower down, it makes the climb harder for the blood and can encourage it to stay in the lower leg, which is called venous hypertension (blood pools and presses inside the vein).
For the same reason, these garments need to reach at least to just below the knee: an ankle sock does not reach the calf, which is one of the two pumps that push blood upwards.
Is tighter better? Calf sleeves and footballers
Seeing how it works, it would be easy to think that the tighter a garment, the better. Where it squeezes counts as much as how much: a garment that presses harder on the calf than on the ankle makes the climb harder for the blood, as we have just seen with the toothpaste tube.
What are calf sleeves for?
Calf sleeves are an elastic tube that covers the calf and leaves the foot and ankle free. You see them a lot at popular running races and for recovery. As they do not reach the ankle, they miss the area where graduated compression squeezes most and where it starts pushing blood upwards. A graduated compression sock up to just below the knee covers the whole stretch. What the studies say about compression in sport is summed up in what compression socks do for sport.
Why do footballers cut holes in their socks?
If you watch football, you will have noticed the holes some players have in the back of their socks, at calf height. At Euro 2024, England players such as Jude Bellingham, Bukayo Saka and Conor Gallagher wore them2. Their teammate Kyle Walker had already explained it in 2021: the socks were too tight and put pressure on his calves, so he cut holes in them2.
Bethany Tomlinson, a physiotherapist at AXA Health, explains it like this: during a match the calf works, receives more blood and gains volume, and a tight sock adds pressure right there. The holes aim to relieve it. She herself acknowledges there is limited scientific evidence that it improves performance3.
Notice where it bothers them: at the calf, which is exactly where graduated compression squeezes least. And if a compression sock feels tight on your calf, check the size first, which is chosen by measuring the leg (the foot stays loose whichever size you pick). You will find the measurements in the size chart.
And the rules? As far as socks go, IFAB Law 4 requires any tape or material applied or worn externally to be the same colour as the part of the sock it covers4.
“If a garment bothers you on the calf, what you need to check is how it distributes the pressure and whether the size is right. In a well-made compression stocking, the pressure is highest at the ankle and decreases towards the knee.”
Dr. Erica Homs Romero, nurse specialising in vascular health and lecturer in Nursing at the University of Girona
Calcetinos, graduated compression socks to lighten your legs
Placed next to the scale above, Calcetinos sit below it: they are light graduated compression socks, 14 to 17 mmHg tested in an external laboratory, for everyday wellbeing. They are not a medical device and are not available on prescription: if your doctor has prescribed a specific compression, that is the one you need.
They are designed to ease the feeling of tired, swollen legs, which is why they go well with:
- People who work on their feet all day, such as healthcare staff, construction workers, waiters, shop assistants, flight attendants...
- People who work sitting down all day, such as call centre staff, analysts, programmers, receptionists and office workers in general.
- Pregnant women.
- Athletes who want their legs to recover better after training.
Graduated compression socks are worn during the day and taken off at night: lying down, compression adds nothing, and your skin appreciates a few hours without fabric on it. We go into more detail in whether you should wear compression socks to sleep. When you take them off, alternating cold and lukewarm water on your legs in the shower gives your veins an extra push to work.
Give your legs a hand with Calcetinos, and remember that not all compression socks are Calcetinos… or the same 😉
Sources
- Farmalastic (Laboratorios Cinfa). Diferencias entre medias de compresión y de descanso (in Spanish). Sets out the usual scale in Spain: light 18-21 mmHg, normal 22-29 mmHg, strong 30-40 mmHg and very strong above 40 mmHg. Link
- Taylor L. Why have the England players cut holes in their socks for the Euros? PA Media, 18-06-2024. Includes Kyle Walker's comments to SPORTbible in 2021. Link
- AXA Health. Physiotherapist reveals the reason why footballers cut holes in their socks. 03-06-2026. Link
- The IFAB. Laws of the Game, Law 4: The Players' Equipment. Link
