Seeing Spots on Rio Athletes? It’s Because They’re Into ‘Cupping’

If you’ve been following the Games in Rio, you’ve probably noticed a new kind of Olympic ring. Athletes are sporting huge, circular purple marks that look like skin outbreaks but are actually bruises left behind by an alternative medical treatment called cupping therapy, according to online sporting community SB Nation.

On Sunday night, swimming champion Michael Phelps set social media on fire when he revealed a torso covered in purple bruises during a television broadcast of the U.S. men’s 4×100-meter freestyle relay (where he won his 19th Olympic gold medal, by the way). Some were concerned about Phelps, but others knew the marks were telltale signs of cupping therapy — and even joked that Phelps looked like he was in a fight with an octopus!

But Phelps is clearly a devotee of the treatment and even posted a picture of his cupping procedure to Instagram, giving a grateful shout-out to his practitioner.

So what is cupping therapy? According to cupping practitioner Lily Lai, who is also an acupuncturist and an expert in herbal and Chinese medicine, “Cupping essentially involves creating negative pressure within a cup while it is in contact with the skin. The cups can be retained for five to 20 minutes and are usually placed on areas of thick musculature such as the back, shoulders, and buttocks.” She adds that cupping therapy is “an ancient medical intervention that has been practiced in Asian and European cultures. It is closely related to traditional Chinese medicine.”

Treatment involves placing special glass cups on the skin and using a flame to create a suction that opens pores and increases blood supply to muscles and skin, according to Lai’s website, helping to treat pain, soreness, or numbness in the neck, shoulder, and back, fight respiratory ailments, combat digestive disorders indigestion, and even relieve stress and anxiety.

Another cupping practitioner, John Tsagaris, a world-renowned doctor of traditional Chinese medicine, explains the logistics of the procedure, saying, “Cupping works in an opposite way to massage. Massage applies pressure to the skin and the muscles to affect an area; cupping applies suction to the skin and tissues to stretch them upward.” Tsagaris adds that the treatment helps to “enhance circulation, remove toxins, provide pain relief, and clear inflammation, all of which may be lingering in your body’s tissues.”

According to WebMD, cupping is also used as a form of detox, to aid in fertility, and to treat skin problems, migraines, arthritis, high blood pressure, and anemia, among other afflictions.

Though it seems the Olympians are treated by practitioners, Lai says that cupping can be applied by athletes themselves “by placing specially devised plastic cups onto the skin of the affected areas and a manual pump to withdraw the pressure from within.”

Related: 13 American Olympians With Enviable Hair

Though Tsagaris assures Yahoo Beauty that cupping “feels very pleasant,” U.S. swimming star Natalie Coughlin might beg to differ. On her Instagram account, Coughlin recently shared a picture of the medieval-looking procedure with the caption: “Laughing because it hurts so bad. Gonna leave a mark! #AthleteLife.”

But don’t misunderstand: Coughlin takes her cupping sessions seriously and won’t let anything like a silly fire drill stand in the way of treatment.

Other athletes spotted with cupping bruises at the Olympic Games this year have included gymnasts Alex Naddour and Chris Brooks.

While cupping is the treatment of the moment for Team USA in Rio, it’s definitely not the first time the medical treatment — which dates as far back as 1500 B.C. — has made headlines. According to the Daily Mail, fitness-obsessed celebs like Jennifer Aniston and Gwyneth Paltrow have undergone the procedure in the past, with Aniston sporting the circular spots on her back at a movie premiere in 2013 and Paltrow showing off her cupping bruises as far back as 2004.

In 2010, Jessica Simpson tweeted about her love of the time-honored ritual, according to E! Online. “Shocked my system with a vegan diet, special Pu-erh tea from China, and cupping since Friday!” she wrote, and — just to clear up any possible confusion —she added, “this has NOTHING to do with weight! It is about understanding my body through hydration and alkalinity.”

And a few years ago, Lena Dunham boasted her love of the ancient ritual by posting a pic of her bruises to Instagram.

Last year, a newly clean-living Justin Bieber was photographed with cupping bruises on his body as he emerged looking overjoyed from the Bondi Icebergs swimming pool in Australia.

It’s important to note, though, that — like most Eastern medical practices — cupping therapy has its detractors. Major athletes and celebrities and other fans of Eastern medicine may swear by the practice, but experts in Western medicine hesitate to vouch for the alternative treatment’s effectiveness. WebMD notes that the American Cancer Society has stated: “Available scientific evidence does not support cupping as a cure for cancer or any other disease. Reports of successful treatment with cupping are mainly anecdotal rather than from research studies.”

Rest assured that — botched procedures aside — the treatment is not known to cause permanent harm. According to WebMD, it can cause mild discomfort, bruises, burns, and skin infections, though, so it’s important to research and identify responsible practitioners if you’re looking to hop on the cupping bandwagon.

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