{"id":152848,"date":"2025-12-17T11:01:50","date_gmt":"2025-12-17T16:01:50","guid":{"rendered":"https:\/\/runningmagazine.ca\/?p=152848"},"modified":"2025-12-17T11:05:15","modified_gmt":"2025-12-17T16:05:15","slug":"shocking-japanese-recovery-technique-what-does-the-science-say","status":"publish","type":"post","link":"https:\/\/runningmagazine.ca\/the-scene\/shocking-japanese-recovery-technique-what-does-the-science-say\/","title":{"rendered":"Shocking Japanese recovery technique: what does the science say?"},"content":{"rendered":"

Warm baths have been proven to be effective not only for recovery, but, more recently, for performance, too. But are the effects enhanced by running a live electric current runs through that bath?<\/p>\n

What is the denki buro?<\/h2>\n

The denki buro, <\/em>or electric bath, has been around Japan since before 1928. These small baths, located in public bathhouses (onsens\/sentos<\/em>), are equipped with steel electrode plates on either side, delivering alternating electrical currents while the bather is submerged. At first glance, electric baths appear identical to standard public baths, often without warning signs or instructions for use.<\/p>\n

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Japanese bathhouse. Photo: W\/C<\/figcaption><\/figure>\n

During my trip to Japan for the World Athletics Championships in September, I visited a local bathhouse. Speaking from personal experience, getting into an electric bath when you’re prepared for it is one thing; stepping into one unexpectedly is a unique and shocking experience (pun intended). After years of being taught that electricity and water is a deadly combination, I found the sensation alarming\u2013my muscles completely seized up, I was unable to extend my wrists and I felt sharp pins and needles (known as piri piri <\/em>in Japanese) all over.<\/p>\n

What science says<\/h2>\n

According to a study published last year<\/a> in the Journal of Interventional Cardiac Electrophysiology,\u00a0<\/em>the output voltage is restricted to a maximum of 10 volts, while frequency is set between six and 60 hertz (depending on the setting). “Denki buro<\/em> is said to improve blood circulation by directly stimulating the muscles,” the study states. “However, there is no evidence to confirm this.” Sources also report benefits to include relief of joint pain and muscle tightness.<\/p>\n

But like many wellness and recovery protocols, scientific evidence of supporting their effectiveness is limited, with little proof that they deliver meaningful benefits.<\/p>\n

\"sore<\/p>\n

Is it worth the risk?<\/h2>\n

The case study, however, did find a big reason\u00a0not <\/em>to use the denki buro;<\/em> the baths pose a serious risk of being mistaken for ventricular fibrillation (VF) by an implantable cardioverter defibrillator (ICD), which can lead to inappropriate ICD shocks (which can be painful and can reduce ICD battery life). The tubs, despite often being unmarked in public bathhouses, are also not recommended for people with medical or heart conditions.<\/p>\n

Many tourism websites<\/a> rave about the denki buro,<\/em> stating things like, “you should feel invigorated when you get out.” This particular website also warns users: “Please do not use the electric bath if you feel pain on entering or have any health problems, like a pacemaker. The recommended time to soak in an electric bath is only three to five minutes, so make it quick.”<\/p>\n

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Stick to what you know<\/h2>\n

On its own, hydrotherapy (i.e. hot tubs, ice baths<\/a> and aquatic therapy), when done correctly, is a well-established tool for relaxation, recovery and fitness. Hot-water immersion can soothe sore muscles, increase blood flow and has even been shown to improve VO2 max by up to four per cent in as little as five weeks.<\/a><\/p>\n

Electrotherapy is another commonly used recovery and pain-management method, delivering electrical impulses through electrodes placed on the skin\u2013techniques many runners might recognize from physiotherapy.TENS (transcutaneous electrical nerve stimulation) is widely used to stimulate nerves and reduce pain, while EMS (electrical muscle stimulation) causes involuntary muscle contractions, aiding strength, function and relaxation, especially during rehab after injury or surgery.<\/p>\n

So, as fun as getting zapped in a hot tub sounds, it’s probably best to stick to your classic electrotherapy and hydrotherapy procedures separately\u2013especially if you have a medical condition. And if you’re headed to a public bathhouse in Japan anytime soon, enter tubs at your own risk.<\/p>\n

Are warm baths the secret to getting faster?<\/a><\/p><\/blockquote>\n