Compression socks were everywhere at Kona in 2007, and continued to increase in popularity as well as credibility in 2008. Now the popularity is growing with many different manufactures bringing compression socks as well as other compression products to market. Compression is not a new technology; it has been used for years in medical patients with venous and arterial insufficiency. However, the application of this technology to athletics is relatively new. In this article we will take a closer look at the science and physiology behind compression.
First a short physiology lesson just to make sure we are all on the same page. Oxygenated blood is carried from the heart to the periphery and working muscles via arteries. The deoxygenated blood and muscle waste products are brought from the periphery back to the vital organs via veins. Arteries are more elastic which are able to stretch to accommodate the pressure with each heartbeat, this is why you can feel your pulse. Additionally arteries contain muscle in the wall which allows them, in conjunction with various other body signals and systems, to expand or compress to regulate blood flow and blood pressure. Veins, however, are very thin walled and have no muscle or resting tone and simply collapse when not filled with blood. They rely on working muscles, around them and a system of one-way valves to return blood toward the vital organs. Arterial blood flow is much more closely regulated and precise while venous flow is much less regulated.
Much of the empirical research regarding compression focuses on blood flow at rest, because this technology was first used to help people with peripheral vascular disease. There is clear evidence to support compression use in promoting recovery. There is clear evidence that compression socks after a race or hard workout provide benefit. These garments will help to avoid venous stasis (blood pooling in the legs) and swelling. Compression is particularly helpful in depended areas of the body, such as the feet and lower legs where gravity has a greater effect on blood return. Improved blood flow after a workout results in enhanced nutrient delivery and removal of waste products to and from muscles. This creates a situation optimal for muscle repair, reduced stiffness and heaviness in the legs and possibly less soreness. There have been mixed results examining exactly how compression socks benefit recovery. Several studies have demonstrated that post exercise blood lactate levels were lower with compression sock use both during and after exercise. Other studies have demonstrated that compression socks do create a major fluid shift in the body.
Only relatively recently has the effect of compression been examined on exercising athletes, or even healthy people for that matter. As a result the studies examining compression and exercise are limited and further research is needed. However, that being said there have been some preliminary studies that have shed some understanding of how compression garments affect blood flow and muscle function during vigorous exercise. Compression garments are believed to improve venous blood return to the heart and allow for better cardiac output (flow of oxygenated blood from the heart) thereby aiding oxygen delivery to working muscles and increased endurance. There is less research examining and understanding the benefit of compression to the arterial circulation. It is clear that the musculature of the arterial wall reacts to changes in pressure, both pressures inside as well as outside the vessel. Some studies’ claim is that compression socks increase the ambient pressure outside of the arteries. As a result the musculature in the arterial wall relaxes due to this ambient support and increases in diameter resulting in greater blood flow through the arteries.
There have been several other studies demonstrating other benefits of compression garments. Some research has shown that compression garments may improve neuro-muscular connection and coordination. A recent study demonstrates that wearing graduated compression stockings during a 10-km road run appears to reduce delayed-onset muscle soreness after exercise. The material that certain compression garments are made from, such as RECOVERYSOCK contain cooling properties that maintain a lower peripheral temperature, than conventional socks when they are wet, which can have large impact on muscular function.
Lastly, it is important to keep in mind that with many different brands flooding the market not all compression wear is created equal. It is important to select a brand that has been making compression garments for a number of years, probably for medical use, prior to developing a compression garment for exercise. The compression socks (that cover the entire foot) also seem to have better evidence to support improved blood flow than simply a compression cuff or sleeve. Additionally, determine the specific level of compression and difference in various parts of the garment. There is a balance between too much compression that will actually impair blood flow and not enough compression to have any benefit. As a general rule of thumb the compression should be highest at the most distal part (farthest away from the heart) and then lowest at the most proximal position (nearest the heart) with either consistent or graded compression between these two points. All that being said RECOVERYSOCK has been one of the pioneers to bring compression technology to athletic activity after producing medical compression for many years and RECOVERYSOCK is also a very popular brand for comfort and cooling properties as mentioned above.
With all of the information to try to digest regarding compression it is important to keep in mind there are many athletes and coaches who, from personal experience, feel that compression garments aid in both performance and recovery. I must admit that I am included in this group. Many athletes report decreased soreness after workouts in which they wear compression garments and there are a few studies confirming this experience. The use of compression garments in exercise is relatively new and the next several years may provide more studies and research on the topic. There is clear objective data to support the benefit of compression garments after a workout, and at this point only preliminary evidence for their use during a workout, however, after wearing them many people are strong believers in the benefits of compression.