That prickly sensation on the top of my skull?
It’s just a couple of milliamps of positive electric current, roughly the same amount used to power your average household smoke alarm, flowing directly into my brain’s motor cortex. Suffice it to say: I’m a little uneasy about it. I’m sitting in a windowless lab, quietly gazing at stark white walls as my head continuously absorbs the tiny electric stabbings. No matter how hard I try, I can’t shake the image of a young Jack Nicholson thrashing his way through electroshock therapy in One Flew over the Cuckoo’s Nest. But unlike his electric current, mine is actually deemed safe, and the man administering my treatment is no Nurse Ratched. His name is Aaron Wayne. A former captain of Stanford’s swim team, Wayne works as a field research engineer for San Francisco–based start-up Halo Neuroscience. I’m testing out the company’s debut product, the Halo Sport: a set of earphones—lined with rubbery spikes—that, the company says, supercharges your brain for the sake of fitness.
I’m also exercising. With the headset firmly on, I’m seated at a specialized curl machine with a few electrodes attached to my arm to measure my power output. Every time I do a curl, a blue line on a computer screen across from me jags up to a peak when I lift and drops off when I finish.
Wayne performs tests like this one all day, on hundreds of subjects, trying to understand how Halo’s technology affects different kinds of exercise. In the three years since Halo launched, the company has run more than 2,000 test sessions, which have produced, the company says, clear positive results. When the Halo Sport goes on sale to the public this month ($749, from haloneuro.com), new buyers won’t be the first to use it. So far, several Olympians who competed in Rio de Janeiro this summer, dozens of NFL and MLB players, top trainers, and even members of the U.S. Special Forces have already begun using early versions of it.
Created by a soft-spoken Stanford-trained M.D. named Daniel Chao, Halo uses a process called transcranial direct current stimulation (tDCS)—neuroscience-speak for sending a low electric current (1.4–2.1 milliamps, or about what you’d find in a nine-volt battery) into a targeted part of the brain and exciting the neurons, thus making them more likely to fire and create new neural pathways. This, in turn, makes the brain temporarily better at hard-coding what you’re doing. So when you stimulate the motor cortex—the part of the brain that controls movement—and pair that stimulation with a workout, you get better at the exercises in that workout, and more quickly than you would otherwise.
“Most people think the brain’s role in exercise has to do with the mechanics of precise skill, like shooting a free throw or putting a golf ball,” Chao says. “And that’s true—skill is neurologically governed. But what about how strong we are? When people do strength training by lifting weights, they think it’s all about the muscles. But with repetition, you’re also training the brain to master those movements.” In other words, strength isn’t just about how big your muscles are but how well you can control them. And the Halo Sport, Chao says, will sharpen that process and essentially make your workouts better and more efficient. As a result, you’ll get stronger and bigger a whole lot faster.
It sounds crazy, I know. But thousands of independent studies have examined tDCS in the past decade and shown positive effects on everything from memory to mood disorders, depending on what part of the brain you zap. “It’s not just about getting stronger faster. It’s about learning faster,” Chao says. “Theoretically,” says Vince Clark, director of the University of New Mexico’s Psychology Clinical Neurosciences Center, who has studied tDCS extensively, “[the Halo Sport] should work.”
Which raises a question: What can it do for you? I’m going to keep doing curls to find out.
Hours before my headset test, I’m chasing Chao up a San Francisco hill on a road bike. A passionate cyclist for as long as he can remember, he appointed himself one of Halo’s first test subjects when he started developing it.
“I was logging about 7,000 miles a year,” he says, “but I’m in my mid-40s now, and my PRs were set, like, 10 years ago. I got to the point where treading water had become the goal.” With the Halo Sport, he started doing interval training on a stationary bike and pounding out laps at the cycling oval in Golden Gate Park.
Just north of the Golden Gate Bridge is Hawk Hill, which Chao had long failed to climb in less than eight minutes. “So one day I decided to give Hawk Hill a go again, and my time was 7:45. To make sure it wasn’t a fluke, I did it again—I wanted to cement that puppy.”
Equal parts jock and geek, Chao grew up in Anaheim, CA, studied biochemistry at UC Berkeley, and earned a master’s and an M.D. at Stanford, where he also caught the Silicon Valley start-up bug. “When I think about my entrepreneurial friends, many of us can identify a kind of fuck-you moment, when something led us to say, ‘Why is it like this? We should be doing it entirely differently.’”
For Chao, that moment came during pharmacology class, when he was learning about drugs for the brain. “They all suck,” he says. “You have to put up with a bunch of side effects to get the benefit.” Unlike other organs, the brain is protected by a so-called blood-brain barrier, which makes it difficult for drugs to get through. And once they’re in, they go everywhere, not just where you want them to go. So Chao thought to himself: “The brain is an electrical organ; why not speak its language and use electricity to affect it?”
He eventually landed a job at a bio-tech start-up called NeuroPace, which made an implantable device to treat epilepsy with deep-brain electrical stimulation. After years of gathering data and pursuing the “long, arduous journey of working with the FDA,” NeuroPace got approved; but by then Chao and a co-worker, a biomedical engineer named Brett Wingeier (now co-founder of Halo), felt another fuck-you moment coming on.
They’d been paying attention to a growing body of research showing that electrical stimulation from outside the head—tDCS—could affect the brain’s performance in other ways, and with big results. So they started testing potential tDCS products by targeting different brain functions. Eventually, when their research showed dramatic results in the motor cortex, they created a fitness device that buzzes that area. After raising money from some of the most powerful people in Silicon Valley, including venture capitalist Marc Andreessen, Chao and Wingeier set out to design a friendly-looking gadget that would minimize the perception of freakiness—hence the headphone shape, which strongly suggests a set of cans from Beats by Dre. (The former Beats CEO is on Halo’s board of advisers, and yes, you can listen to music through the Halo Sport headset, too).
They also came up with new vocabulary for the process of tDCS: not “zapping” or “charging”—the official jargon is “priming.” And for the record, you wear the Halo Sport before a workout, not during. “A typical use would be to wear it for 20 minutes while warming up,” Chao says, “then take it off and feed the brain as many quality reps as possible over the next hour.”
To help test the device, the founders immediately turned to top athletes, first partnering with the U.S. Ski and Snowboard Association. Over four weeks, seven members of the Olympic ski jumping team trained with the Halo Sport, jumping off a sled attached to a force plate, while others trained on the same rig without it. At the end, the Halo group’s “jump force” had improved 31%, compared with only 18% for the non-Halo jumpers.
In another study, 10 top college athletes from various sports who trained at Michael Johnson Performance (MJP), the former Olympic champion’s facility in Texas, used the Halo Sport while doing a five-week lower-body strength program. As measured by three squatting and jumping exercises, the Halo group saw a 12% gain in explosiveness, compared with a mere 1.7% for a control group.
Halo will “rewrite the way we think about training the body by focusing on what we can do above the neck,” says Lance Walker, MJP’s global director of performance. The list of elite believers goes on: Oakland Raiders cornerback T.J. Carrie, several Olympians who competed in Rio (including the U.S. sprinter Michael Rodgers), and three Major League Baseball teams are all using the Halo Sport.
Not that there are no unanswered questions.
“We simply don’t know about long-term safety,” says UNM neuroscience head Vince Clark. “There are studies that have to be done about the long term.” If and when those studies happen, they won’t be conducted by the FDA. Because Halo Neuroscience is selling the Halo Sport as a gadget and not a medical device, it won’t be regulated.
Clark also speculates that the Halo Sport may sidestep an important self-control mechanism in the brain that keeps us from overexerting our muscles and hurting ourselves. “This is just a hypothesis, but it’s clear that people are capable of unusual amounts of strength in extraordinary circumstances. Why can’t you normally access that? Your brain is regulating your muscles to protect you.”
Even I have to confess that I’m not likely to strap on a Halo Sport again anytime soon. Call me crazy, but despite the number of people who I hear have donned the headset harmlessly, and the reams of research that have shown the worst short-term adverse effect of tDCS to be a little temporary redness on the scalp for some users—or the prickling I felt—the idea of shooting electricity into my brain will definitely take some getting used to.
Back at Halo, after doing my curls, I learn my results: Lifting four different weights, my muscles produced an average of 5.4% more joules of energy during my Halo Sport–powered curls than during my earlier, non-Halo curls. Though it was only one session, the gains were consistent across weight levels. They’re also consistent with the results of myriad other testers, many of them serious athletes.
“The data certainly suggest that Tom’s biceps muscle is able to produce more energy during [tDCS],” Halo concluded.
With results like these, you can expect the Halo Sport to become a fixture among competitive athletes, who seldom pass up a way to gain an edge. The company has already started selling to pro teams and the military. Granted, at $749, the headset price is high, but Halo plans to sell to gyms and trainers as much as (or maybe more than) to individuals, so gym goers with a competitive streak can reserve a headset, maybe for a small fee, or use one with a Halo-certified trainer.
If early adopters like Emily Hu—a medical device engineer by day and world-record powerlifter by night—are any indication, the Halo Sport will face an uphill battle getting gym goers zapping. Hu holds the all-time highs in bench and deadlift for her weight class. She heard about the device earlier this year and contacted the company to see if it would let her test the device—she’d worked with tDCS in clinical trials and felt perfectly comfortable with the idea of using it for fitness.
“Within a week, I hit a phenomenal PR in squats, my weakest link,” she says. “I can usually go up two or three pounds per workout, but this was a nine-pound jump—that’s huge.” Her gym mates, on the other hand, the very people witnessing her progress with the Halo, can’t bring themselves to try it. “I get a lot of funny questions,” Hu says. “Like, ‘Can you make yourself stupid doing this?’ Some guys say they don’t think it’s dangerous, but when I offer to let them try it, they say, ‘No, thanks. I’ll just drink Creatine.’ So it’s not for everyone.”
But athletes may just be the tip of the spear. The week before I visited Halo, U.S. Secretary of Defense Ashton Carter announced that the department’s Defense Innovation Unit Experimental (DIUx) had just signed its first contract with a tech firm: Halo Neuroscience.
“These headsets will be used by teams from our Special Operations Forces, who will work with Halo to gauge how effective their device might be at improving marksmanship, close-quarters-combat skills, and overall strength training,” he said.
The world’s most elite fighting force is never afraid to try something new. Are you?