Compression Clothing: Will It Really Improve Your Workout?

Between all the high-tech activewear on the market, tools touted for treating sore muscles, and #fitspo Instagrammers always telling you what to do, it can be a workout in itself just to stay on top of what information qualifies as valid. Take compression clothing, for example. Every other marathoner, cyclist, or gym-goer is sporting a sleeve of some sort these days, but do they really help?

Read on to learn what compression clothing does, whether or not it can help you, and how to use it correctly.

What Is Compression Clothing?

Compression sportswear ranges from socks and sleeves to shorts and shirts all aimed at reducing muscle soreness, expediting recovery, and according to some claims, improving performance. The caveat with compression clothing, however, is that its manufacture isn’t regulated. “Someone can put ‘medical grade’ on a product and it may be supportive because it’s tight,” says Jared Finney, national sales manager for CEP Compression Sportswear, “but there is a difference between supportive compression and therapeutic compression.”

Supportive compression is basically a tight sock or shirt. Medical grade, or therapeutic, compression is any garment rated at 20 mmHg (millimeters of mercury, a standard unit of pressure) or higher, though researchers have yet to arrive at consensus on the level or type of compression recommended for performance and recovery.

When it comes to socks or calf sleeves specifically, the key component of therapeutic compression is that the sock is tighter around the ankle and looser around the calf. “You need to have a graduated compression,” says Jeff Irvin, a former sales manager with Medi, a medical-grade compression company that started CEP. Irvin, now with CEP, says that a true graduated compression garment needs to be tighter on the extremities and looser as it nears the core.

What Does Compression Clothing Do?

Using the calf sleeve as an example, Chung Sim Lim, MBBS, PhD, FRCS, a vascular and endovascular surgeon in London, explains, “Graduated compression wear is thought to work by providing support to the vein and lymphatic drainage system to make sure blood flows in the correct direction and reduces pooling of fluid in the ankle.” As you work out, oxygenated blood from the heart is delivered to the rest of the body. After the oxygen is absorbed and used by muscles and skin, the deoxygenated blood is sent back to the heart—this last step, Lim explains, is where graduated compression is supposed to work its magic.

The pump for the veins, he says, is not the heart but the muscles, which squeeze blood in the veins when they contract, driving blood flow. Valves in the veins of the legs and arms ensure blood travels in one direction—toward the heart and against gravity when we’re upright.

However, “a relatively large proportion of healthy people have some degree of leaky valves in the veins of their extremities, particularly the legs,” Lim says. “As a result, some of the fluid or blood will pool in the ankles from gravity. This fluid may leak into the surrounding tissues and cause some degree of inflammation or irritation that may be perceived as ache, fatigue, ankle swelling, pain, restlessness, and discomfort.”

According to Lim, therapeutic compression wear may also offer joint stability—not the kind you get from a knee brace, but the kind that helps absorb shock. An analysis in the American College of Sports Medicine Health and Fitness Journal suggests that compression garments may decrease muscle oscillation (the vibrations sent through your leg muscles as your foot strikes the ground ) during running and other high-impact workouts. The resultant reduction in reverb helps improve mechanical efficiency, which may result in better performance. Of course, Lim also notes that more research is needed in order to make concrete claims about what compression wear can and can’t do.

“Some hypotheses suggest that compression may increase oxygenation of the tissues, improve muscle repair and recovery, reduce inflammation, and improve the biomechanics of exercise, though all these remain to be proven,” he adds, noting the possibility of a placebo effect as well. For example, a study in the British Journal of Sports Medicine concluded that using compression garments as a recovery tool, such as after exercise, may aid in reducing perceived muscle soreness and post-exercise trauma. Nevertheless, athletes in most studies do self-report less soreness after using compression.

Does Compression Clothing Work?

There’s less consistent evidence, however, of real physiological benefits. For example, a 2008 study in the International Journal of Sports Physiology and Performance found that, while the group of rugby players it tested self-reported reduced muscle soreness, the use of compression garments didn’t affect their performance.

A 2013 meta-analysis in the same journal found modest positive effects of compression wear on the performance of specific movements, chiefly sprinting and jumping. It also found small-to-moderate positive effects on recovery of strength and power (jumping), delayed onset muscle soreness (DOMS), muscle swelling, and blood lactate removal—though the compression garments had to be worn for 12-48 hours after exercise. The results suggest that compression clothing may provide some physiological benefit, but that more research is needed.

Other types of compression wear include posture improving shirts for cycling, like those marketed by Skins, though research has yet to support physical benefits here as well. According to a 2014 study in the Journal of Chiropractic Medicine, cyclists wearing a posture-corrective compressive shirt did self-rate a positive experience with regard to riding posture, post-ride posture and recovery, and spine discomfort, though no physical or physiological variables were tested.

How to Shop for Compression Clothing

Again, compression garments are unregulated as sportswear, so you need to do your diligence to make sure what you’re buying provides true compression. CEP sells socks offering graduated compression that delivers more than 20 millimeters of mmHg. Smartwool also makes graduated compression socks in over-the-calf versions for both men and women that use a 20-30 mmHg rating for compression. 2XU offers a variety of compression tights and shorts with an mmHg fit of 20-25.

For sizing, Finney says, “The single biggest thing a consumer can do when they are shopping for compression is to make sure the sizing is measuring the part of the body that’s being compressed,”such as the calf or arm width. “If the sizing is just based on foot size, that’s a red flag.”

How to Use Compression Clothing

Although therapeutic compression wear is available for the upper body and arms, you’ll see the greatest benefits in the lower body during activities like running, cycling, and strength training. These benefits are due mainly to gravity, explains Lim, who says that leaky valves are more common in lower than upper limbs. During a workout, wearing a sleeve or a sock could help to recirculate blood back to your heart.

For post-exercise recovery, however, Irvin says to make sure you’re wearing a sock (i.e., supportive) and not a sleeve (i.e., therapeutic). “Sleeves are not recovery items,” he warns. “If you are not being active, do not wear a sleeve.” Doing so during rest, he explains, will only lock fluid in your feet, causing them to swell. So use sleeves only when being physically active, not recovering (or, for instance, when sitting on a plane).

The amount of time you should wear supportive compression for recovery is up to you. Irvin puts on a sock right after a workout and is comfortable wearing them for the rest of the day. Other athletes might find a few hours is enough for them as they notice their legs starting to feel better and loosen up. Since the benefits of compression clothing so far largely involve perceived reductions in soreness and discomfort, the non-graduated version can be worn as long or as little as you want.