A handful of athletes competing at the Summer Olympic Games in Rio next week will arrive having tried to boost their performance using an unconventional (and not-yet-banned) technology: brain stimulation. The technique, called transcranial direct current stimulation (tDCS), involves channeling a tiny current through specific regions of the brain, making neurons in that area more likely to fire.
The company behind the technology, San Francisco-based Halo Neuroscience, announced last week that at least five athletes competing in Rio have trained with its brain stimulation device. The opening ceremony for the Games is this Friday.
Halo’s device, called Halo Sport, is designed to increase the brain’s ability to adapt to training. Athletes wear the headset while warming up or practicing their skills. Within the headset are electrodes that are pressed to the top of the head. A small electric current is turned on, delivering about 1.5 to 2 milliamps to the brain’s motor cortex. The current gives the neurons in that area a boost, making them more likely to fire.
The firing of neurons puts the brain in a state of hyperplasticity, making it more adaptable to learning, says Daniel Chao, CEO of Halo. Chao calls it “neuropriming.” Those activated neurons communicate with muscles, and theoretically, the repetition of sending electrical signals along neural circuits during practice makes those pathways easier for signals to follow in the future. The result: Athletes perform their skills better, even without the headset, says Chao. “It’s a training device, not a day-of-performance device,” he says.
That’s the theory at least. And some Olympic athletes are giving it a try, including Mikel Thomas, a 100-meter hurdler from Trinidad & Tobago who made his first Olympics appearance in 2008 in Beijing. “He said he felt more fluid with his technique,” after training with the device, says Chao.
Hafsatu Kamara, a 100-meter sprinter from Sierra Leone who will be running in her first Olympics reported to the company that after training with the device she set a new personal record for how hard she can thrust her hip, Chao says. The athletes were not able to speak with IEEE Spectrum about the device due to a new rule limiting media exposure for brands that are not official Olympic sponsors.
Other Olympic athletes that trained with the device, according to Halo, include three Americans: Michael Tinsley, a 400-meter hurdler Mike Rodgers, a 4x100-meter relay sprinter; and Samantha Achterberg, a modern pentathlete.
And it’s not just athletes that are willing to give it a go. U.S. Defense Secretary Ashton Carter last week said military special operations teams would try out Halo Sport to see how effective it could be at increasing their skills. The plan is part of the Department of Defense’s DIUx program, or Defense Innovation Unit Experimental, which aims to connect the military with innovative tech companies. Chao said he could not reveal any details about Halo’s contract with the DIUx program.
The London Times last week reported that Britain’s Ministry of Defense may follow DIUx’s lead, but Chao said that was just a rumor. “We haven’t heard a peep from those guys.”
Some athletes will try anything to make just incremental improvements in their performance and recovery. Cryotherapy, where athletes reduce inflammation by hanging out (briefly) in -100 degree chambers, is gaining in popularity. So is neurotraining, which involves monitoring brain activity and making adjustments in performance based on that feedback.
Some athletes go so far as to try experimental drugs and veterinary-only therapies. After all, shaving a few seconds can mean the difference between the cover of a cereal box and never-heard-of-him.
The World Anti-Doping Agency (WADA) has banned hundreds of experimental and commercial drugs deemed to enhance performance. The anti-doping lab in Rio will be looking for such substances in Olympic athletes’ urine and blood samples next week using its state-of-the-art mass spectrometry instrumentation and other testing equipment.
Brain stimulation is not yet on WADA’s prohibited list. That’s partly because it’s unclear whether it actually gives athletes an advantage. A number of academic researchers say they are skeptical of tDCS generally, and doubt many of the claims made by the dozen or so companies that are marketing such devices.
Whether Halo’s device is an exception is unclear. The US Ski and Snowboarding Association last year tested the device on its ski jumpers, and the results are compelling.
And Halo has conducted several double-blind studies that show its device improves athletic performance compared with a sham, or bogus device. In those studies, neither the investigator nor the subject know which device she has, which helps account for placebo effects.
But the company published those studies itself as white papers rather than in peer-reviewed research journals—a practice the company says it plans to change going forward.
IEEE Spectrum’s Eliza Strickland will dig into the skepticism, and even try Halo Sport herself in an upcoming feature story. Look for that online later this month and in Spectrum’s September issue.
Emily Waltz is a features editor at Spectrum covering power and energy. Prior to joining the staff in January 2024, Emily spent 18 years as a freelance journalist covering biotechnology, primarily for the Nature research journals and Spectrum. Her work has also appeared in Scientific American, Discover, Outside, and the New York Times. Emily has a master's degree from Columbia University Graduate School of Journalism and an undergraduate degree from Vanderbilt University. With every word she writes, Emily strives to say something true and useful. She posts on Twitter/X @EmWaltz and her portfolio can be found on her website.
