The Electric Gatorade Acid Test
How biz ar r e ne w technologies ar e unlock ing t he mind’s t r ue po t en t ial f or maximum per f or mance
In sports science writer Alex Hutchinson’s quest to discover the limits of human endurance, he ex plores t he potential for new ways to hack the brain for better performance. Hutchinson travels to Los Angeles and offers himself as the guinea pig, undergoing a series of tests to see if electric stimulation of the brain can provide a measurable advantage for endurance athletes.
Icouldn’t help feeling a little apprehensive as I fitted the headphones over my ears and pressed the electrodes – a fakir’s bed of semi-rigid foam spikes that ran from ear to ear across the top of my head – into my scalp. I’m fond of my brain, and have never had any particular desire to run an electric current through it. But curiosity had trumped my misgivings, so I was about to try the newest thing in next-generation performance enhancement. A Silicon Valley startup called Halo Neuroscience had sent me a pair of their brain-stimulating headphones, which, according to their marketing hype as well as a smattering of academic research, would supercharge my training and boost my endurance. I tapped the start button on the accompanying iPod controller – but instead of a jolt of enlightenment, I got a scolding beep in my ears. “Poor contact,” the iPod admonished me. “Adjust your headset until the coloured bars disappear.”
I had first written about brain stimulation way back in 2013, when a small study from researchers in Brazil showed that 20 minutes of a then-obscure technique called “transcranial direct-current stimulation,” or tdcs, boosted the peak power in a subsequent cycling test by four per cent. This result seemed like a really big deal in the longrunning debate about whether the limits of endurance reside in the mind or in the muscles. If a few volts to the frontal cortex makes you faster, doesn’t this prove that, under normal circumstances, you’re always capable of pushing a bit harder? The idea was fascinating – and also, with the looming spectre of “brain doping,” a bit troubling.
Subsequent studies, though, produced mixed results, leaving it unclear whether the technique really worked. When Halo approached me in the fall of 2016, I couldn’t resist the opportunity to try it for myself. I was writing a book about the limits of endurance, and discovering how to transcend them at the press of a button would make a perfect final chapter, I figured. Except that I couldn’t get the headphones to work. I wiggled the electrodes, adjusted the headphone fit, and re-primed the electrodes with saline solution, but apparently my bald pate, weathered by too many harsh Canadian winters, was impervious to electricity.
Finally, by pressing the headphones into my scalp as hard as I could and holding them there, I managed to achieve electrical contact. When the current started, it felt like ants crawling on my scalp… then like ants biting my scalp… then like acid eating into my scalp. I ramped the current down from a medium setting to the lowest possible, which made it barely tolerable. By the end of the 20-minute neuropriming session, I was a wreck. I had angry red welts dotted across my head where the electrodes had pressed in. I went outside for the fartlek workout I had planned, and ran like crap.
People have been shocking their brains for fun and profit since long before anyone understood what electricity was. Scribonius Largus, the court physician for the Roman emperor Claudius more than 2,000 years ago, recommended the application of a live torpedo fish – an electric ray capable of delivering up to 200 volts at a time – to the forehead for relief of headaches, and other cultures around the world prescribed electric fish for everything from epilepsy to exorcism. The brain, after all, is basically a giant electric circuit composed of neurons that communicate with each other by firing electric discharges. These days, talk of electricity and the brain tends to provoke comments about One Flew Over the Cuckoo’s Nest. But the tiny currents
“If a few volts to the front al cortex makes you faster, doesn’t this prove that, under normal circumstances, you’ re always capable of pushing a bit harder? The idea was fascinating—and also, with the looming spectre of “brain do ping ,” a bit troubling .”
involved in brain stimulation techniques like tdcs, which can be generated with a simple nine-volt battery connected to a couple of electrodes on your head, are 500 to 1,000 times smaller than those used in electroconvulsive therapy. The currents in tdcs don’t cause neurons to fire; they just alter the sensitivity of the neurons, making them slightly more likely to fire (or, if you run the current in the opposite direction, less likely to fire) for about an hour afterward. The precise placement of the electrodes determines which regions of your brain the current f lows through, which in turn determines the effects. There have been thousands of studies in the last few years on tdcs for enhancing learning, fighting addiction and depression, as well as numerous other goals. And after the Brazilian study was published in 2013, the sports world was suddenly interested too.
In 2014, I f lew to Los Angeles to spend a week at the Santa Monica headquarters of Red Bull, the energy drink and extreme-sports behemoth. In keeping with their boundarypushing reputation, they’d brought in five of their world-class cyclists and triathletes to participate in a cross between a training camp and a science experiment that they dubbed Project Endurance. Under the supervision of Dylan Edwards and David Putrino, a pair of Australian neuroscientists from Weill Cornell Medical College in New York, the athletes would be poked, prodded and repeatedly pushed to exhaustion on stationary bikes and then in time trials at a nearby velodrome, with and without tdcs.
For Edwards and Putrino, the Red Bull project was an opportunity to highlight the link between athletic training and physical rehabilitation from conditions like brain and spinal cord injuries, which is their primary research interest. “Whether you’re a highend athlete or a patient fighting locked-in syndrome, you’re dealing with the same limitations of muscle fatigue,” Putrino explained. In either case, the signals that the brain sends to the muscles get progressively weaker as you fatigue – an “in your head” limitation that the researchers hoped brain stimulation might reverse. “The brain is making a choice,” he said. “But the brain’s opinion isn’t always right.”
Over the next few days, I watched the athletes do battle with each other and with their own limits, over and over. It soon
became clear that with a such a small and mismatched group of athletes (a mountain biker, a cyclocross racer, a bmx rider and a pair of Ironman triathletes, one of whom had to drop out because of an injury), it would be impossible to draw any real conclusions about whether brain stimulation worked. Still, it was fascinating to see the athletes wrestle with the idea that their physical limits might not be as immutable as they thought. Getting the athletes to believe this, Red Bull’s chief physiologist told me, was one of the main motivations for holding the camp.
Meanwhile, academic research on brain stimulation’s sports potential continued to produce mixed results. That didn’t stop the idea from being commercialized, of course. In March 2016, as the Golden State Warriors rolled toward a record-breaking National Basketball Association season, power forward James Michael McAdoo tweeted a photo of himself trying out a prototype of Halo Neuroscience’s tdcs headphones. The Warriors are owned by Silicon Valley venture capitalists and have acquired a reputation as “tech’s team,” so it made sense that they would be among the first pro athletes to try brain stimulation – even though Halo’s device hadn’t yet (and, as I write this, still hasn’t) been validated by any peer-reviewed research.
During that year’s nba playoffs, I wrote an article for the New Yorker about Golden State’s use of brain stimulation. It felt like a fairly scathing article to me, essentially labelling the technique as a super-placebo. (“The somewhat circular power of the headphones,” I wrote, “may be that they enhance the benefits of believing in the headphones.”) But in keeping with P.T. Barnum’s dictum about bad publicity, Halo was delighted. They contacted me immediately after the article appeared to see if I’d like to try a four-week trial of the headphones. And, curiosity trumping my misgivings, I said yes.
After my first failed brain-stimulated workout, I got in touch with Brett Wingeier, a neuroscientist with a PhD in biomedical engineering who co-founded Halo Neuroscience in 2013. My struggles were a little unusual, but not unprecedented, he told me – in fact, the post-neuropriming pictures I’d sent him of my pockmarked scalp were pretty much how he looked after using the device. “Most people get the little temporary dimples, related to the mild pressure of the nibs, and a small amount of redness related to increased blood supply in the scalp,” he explained. “Interestingly, it’s guys like us with relatively little hair who have the highest skin resistance. Our skin gets a little tougher from being out in the elements.”
Wingeier gave me some tips on getting the headphones to fit comfortably and increasing the current gradually, and I resolved to keep trying. But I never really got the hang of it. Sometimes it took so long to achieve electrical contact that I would eventually have to give up in order to meet my running partners on time. And when I did succeed in running the current through my brain, the overall discomfort of the experience always left me drained and f lustered, so I never had a good workout. It’s clear that my experience was unusually bad – and this is one of the reasons I don’t put too much weight on first-person product reviews. The leathery toughness of my scalp certainly doesn’t mean that brain stimulation doesn’t work in general. But it did put a damper on my own enthusiasm for the technology.
In the wake of this disappointment, I stopped paying attention to brain stimulation research for a while. The initial excitement of the Brazilian study in 2013 had been followed by a muddle of contradictory results and an overly hasty rush to commercialize the idea. A review
of the field in 2017, from a scientific team at the University of Kent’s Endurance Research Group led by Alexis Mauger, seemed to confirm my growing skepticism. Only eight of the 12 studies they identified showed improvements in endurance following tdcs, and the success rate was even lower in studies of actual exercise like running or cycling (as opposed to contrived laboratory tests like isometric elbow-f lexor endurance).
But hidden among these conf licting results were a few suggestive patterns regarding the best method of applying the electric current. The tdcs stimulation technique involves running a current between two electrodes; the neurons under one electrode get slightly easier to trigger, while the neurons under the other electrode get slightly harder to trigger. It’s possible, Mauger realized, that the positive effects of stimulation in one region of the brain might be cancelled out by negative effects in another region. The solution is to put one electrode on the head and the other on the shoulder, so that the current runs through the brain in only one direction. It’s also not enough to use one pair of electrodes for a full-body exercise like running or cycling – which, after all, involve two legs controlled by two distinct areas in the brain. Instead, you need two pairs of electrodes.
Mauger and his colleagues tried these adjustments in a couple of small pilot studies. They worked. So, in the January 2018 issue of the journal Brain Stimulation, they published a bombshell. They had 12 volunteers complete a series of time-to-exhaustion tests on an exercise bike, with real or sham tdcs using two pairs of electrodes mounted on the head and shoulder. In the placebo trial, the cyclists lasted an average of 10 minutes and 13 seconds in the time-toexhaustion test; with tdcs, they lasted 12 minutes and 37 seconds, an eye-popping improvement of 23.5 per cent. (It’s worth noting
“There is no known way to detect reliably whether or not a person has recently experienced brain stimulation .”
that changes in time-to-exhaustion tests, where the speed or power is fixed, tend to be much larger than changes in races or time trials where you set your own speed. A 23.5-per cent boost in time to exhaustion corresponds to a decrease of two or three per cent in race time – still highly significant, but not of midpack-to-Olympian magnitude.)
While it’s still too early to declare the science settled, Mauger’s results strongly bolster the case that brain stimulation really works to enhance endurance. And that raises some serious and important questions for all of us – athletes, sports officials, parents – to consider. Back in 2013, when I spoke to Alexander Okano, the lead author of the Brazilian study that opened the tdcs f loodgates, he’d warned me that the technique could provide “benefits comparable to using drugs.” He added, “there is no known way to detect reliably whether or not a person has recently experienced brain stimulation.” With no regulation, endurance athletes have already started using it. Ironman triathlete Timothy O’Donnell and Tour de France cyclist-turned-triathlete Andrew Talansky are among those publicly using Halo’s headphones – and that’s probably just the visible tip of a much bigger iceberg. Given Mauger’s findings about electrode placement, athletes may not be getting much benefit from it right now, but it won’t take long for them to start getting it right .
Mauger, despite his scientific interest in what brain stimulation can tell us about the nature of human limits, has similar concerns. “I think this has implications for the ethical use of such methods in sport,” he told me, “and I still have concerns about the safety of these devices, particularly when used regularly for a long period. I would like to see anti-doping and sporting bodies take some initiative on this, and consider whether they think tdcs is something that should be regulated in their sport.”
Not everyone shares these concerns. Nick Davis, a sports psychologist at Manchester Metropolitan University in Britain, has argued that “neurodoping” should not be considered unethical, since it merely helps the brain get the most out of what’s already present in the body. Brain stimulation “mediates a person’s ability but does not enhance it in the strictest sense,” he wrote in the journal Sports Medicine. It’s not cheating, in other words, because it doesn’t alter the physical characteristics that – we’ve always assumed – determine the limits of performance.
I agree that this is an important debate that we need to have sooner rather than later. But to me, Davis’s argument mischaracterizes the essence of endurance. Pushing your limits as a runner has always been as much about the brain as the body – both during the painstaking process of training and in the supreme effort of the race. The greatest champions are those who can harness their minds to squeeze every last twitch from their muscles. To (literally) short-circuit this struggle by making your body’s full measure accessible with the press of a button is to reduce sport to a plumbing contest, where the winner of the race is merely a question of who has the biggest heart and the widest arteries. Part of what gets me out the door on cold winter mornings is the mystery and uncertainty about how deep I’ll manage to dig – so personally, I hope that sports officials will ensure that brain stimulation remains nothing more than a research tool. But then again, maybe I’m just saying that because my scalp is so inconveniently tough.
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