- Compression stocking improve blood flow through veins when at rest.
- Arteries are muscular and have elastic recoil and so can pump blood on their own; veins are inelastic and require external pressure to force blood forward.
- Muscles contract and relax around veins. This is how blood flows forward within them because they are have no elastic recoil like arteries.
- Compression stockings have no logical or evidence-based improvement in performance during sports events because they are of no use when your muscles are already at work contracting and relaxing while running.
- Use compression stocking as a recovery aid after, not during sports events.
I’m an athlete. And I’m a fan. So I admire new running kit, faster, lighter running shoes, the latest GPS sports watch... You get the point! In my admiration of some of my colleagues enviable running gear, I have noticed many competitors donning the latest (and most fashionable) compression stockings. But I just can’t keep the facts to myself when I see them being used during the event.
In the medical field, compression stockings are primarily used to prevent the formation of clots in the larger, deeper veins within the legs. A phenomenon known as 'deep vein thrombosis' (or, a 'DVT'). A clot (or thrombus) occurs when there is decreased flow of blood through veins. This happens when a an individual remains sitting or lying down for a long period of time. For example, during a long flight to an overseas destination or a lengthy hospital admission after a big operation, particularly if it was done on a leg- which obviously prevents you from making any movement at all for a long time. In such situations, compression stockings can be helpful to improve the flow of blood through veins.
But how is it that compression stockings can improve the flow of blood in veins but not impede blood flow through arteries? In order to explain this, we need to get a touch more technical so if you aren't interested in the finer details, go ahead and skip the next three paragraphs underneath and jump to the main points.
VEINS vs. ARTERIES
In simple terms, arteries have thicker, more elastic walls and carry blood rich in oxyen away from the heart to the muscles. Conversely, veins have thinner, inelastic walls and carry blood poor in oxygen towards the heart. From there, that blood is propelled to the lungs which transfer oxygen from the air into your blood.
Another important difference between veins and arteries (and the main point of this article) is the presence of valves which only occur in veins. This is because arteries don't need them! See, when blood is pumped from the heart into an artery, the wall of the artery stretches and becomes wider under the increased pressure. Then, it recoils back into its original state: much like stretching and releasing a rubber band. But because veins cannot do this, they rely on other factors to push blood forward - the muscles . The muscles surrounding veins squash and release veins whenever the muscles contract and relax, functioning much like an external pumping mechanism. Blood is prevented from flowing backwards in the veins by valves which only allow the movement of blood in one direction: upwards. Basically, veins are kind of like a one way street.
Compression stockings don't impede blood flow through arteries because the pressure they exert on the legs is less than that within the arteries. On the flip side, they do work on veins because the pressure is lower within them.
So, let’s recap:
1) Veins need muscles to push blood forward and when the muscles around them are not being used, blood does not flow as well within them and has the potential to form clots.
2) When you are not moving, compression stockings are of benefit in maintaining blood flow through your veins.
THE PROBLEM
Before we dive into this, let me start by saying I am a competitive athlete myself. I use compression stockings for recovery and I understand the ongoing search to find faster ways way to recover, quicker, more efficient running techniques etc. But I am careful to use those methods I know are both logical and backed in evidence. And this is the problem with the use of compression stockings during sport: there is no evidence or logic to suggest that they provide any benefit in circulation during an event!
Remember how muscles push blood up and along veins? Well, during sporting events, your legs are doing exactly that: they are contracting and relaxing overtime and so more than excelling at their job to force blood away from your legs. Therefore, using compression stockings during any sport really makes no logical sense! Why would they be needed to improve circulation when your muscles are doing a good enough job at that already! The pressure muscles exert on veins is far greater than that generated by compression stockings!
CONCLUSION
So should you throw your precious stockings away? Not necessarily. Though I haven't been able to find any evidence supporting the claim tat compression stockings actually do improve recovery (this is subjective, and so hard to assess), it at least seems logical to imagine that they might do so as we know they do at least improve the flow of blood away from the muscles when at rest. The answer? Stop using compression stockings during events and keep them as a method of recovery after your event or training day. Further, use them in conjunction with other methods of recovery: sports massage, ice therapy, heat therapy, stretching, foam rolling etc. After all, two is always better than one, right?