Running on Empty

Updated July 18, 2024 07:44AMIn May of 2012, a thousand of the world’s best ultrarunners were lining up for the start of the Transvulcania Ultramarathon, an 83.3-kilometer course traversing the volcanic outcroppings of La Palma, in the Canary Islands. The atmosphere was taut, a mix of pent-up energy and anticipation, and the runners milled about, checking their watches and exchanging high fives. “Bienvenidos, amigos,” yelled a scrawny Spanish announcer with a spectacular black mullet.At the front of the queue, 34-year-old Mike Wolfe was trying to focus on the day ahead. A thin-faced, introspective Montanan, Wolfe had recently quit his job as an assistant U.S. attorney in Helena to concentrate on running for the North Face’s global athletic team. Transvulcania was his debut as a full-time professional, and even though he had set a course record at Wyoming’s Bighorn 100 in 2010 and won the extremely competitive North Face Endurance Challenge Championship in California’s Marin Headlands in 2011, he felt he had something to prove. A good performance would help validate his unconventional career turn. Lately, however, his 160-mile training weeks had seemed harder than before. He wasn’t sleeping well and was constantly hungry. Just before flying to the Canaries, Wolfe went out for a casual training run with a few friends and could barely keep pace. Five hours later, he inhaled a peanut butter and jelly sandwich at the kitchen table and made an unremarkable entry in the meticulous training logs he keeps: “4:50, plenty of vert. Moved well, tired today with hard pace.” When the gun went off, Wolfe fought to stay toward the front of the stream of Transvulcania runners, which were bottlenecked on the narrow singletrack. He redlined the first 6,000-foot climb with an up-and-coming American, Dakota Jones, and the sport’s reigning king, Spaniard Kilian Jornet. He kept up with the leaders as they strode across the spine of the island, but about halfway through the race Wolfe began to slow. He wasn’t cramping or bonking—he’d experienced those things often enough to know when he’d gone out too fast or not eaten enough. This was different. “I didn’t push myself too hard,” Wolfe, now 37, told me last September, reflecting on the moment when his running career began crumbling beneath him. We were sitting on the grass near the finish of the Rut ultramarathon in Big Sky, Montana, a race Wolfe codirects, watching his 11-month-old son, Colt, play with a box of animal crackers as the last runners came across the line. “It wasn’t like my stomach was bad or I couldn’t eat. It was like my body was just shut down. Like, Nope, you can’t run that hard. I’m not going to allow it.” Eight hours later, Wolfe finished in 13th place, confused and crushed by his performance. It would be another year before he found a label for his ongoing malaise: overtraining syndrome. Anton Krupicka. (Photo: Joel Wolpert) Wolfe’s death march to the finish line at Transvulcania was the beginning of a long and painful battle with the condition, a poorly understood disorder that afflicts endurance athletes training at the outer edges of human performance. Still rare in most power and speed sports, cases of overtraining syndrome, or OTS, have steadily increased in the endurance ranks over the past decade. As ultradistance events have gained popularity, a generation of top ultrarunners are suddenly breaking down faster and in greater numbers. The past seven years have seen the rise and decline of at least a dozen elite competitors, including Anna Frost, who won the women’s division of the North Face Endurance Championship in 2011; Anton Krupicka, two-time winner of the Leadville 100; Geoff Roes, who set a new record at the 2010 Western States 100; and Kyle Skaggs, who demolished the Hardrock 100 record in 2008. Each of them reached the pinnacle of the sport only to mysteriously struggle to repeat their best results. Transvulcania was the start of Wolfe’s own precipitous fall. “OTS is one of the scariest things I’ve ever seen in my 30 plus years of working with athletes,” says David Nieman, former vice president of the American College of Sports Medicine. “To watch someone go from that degree of proficiency to a shell of their former self is unbelievably painful and frustrating.” Nieman, a professor of health and exercise science at Appalachian State University in North Carolina, has spent his career studying the effects of training on the immune system. In 1992, he received the first of a dozen distressingly similar letters from endurance athletes, each of them describing a sudden loss of ability as they struggled with everything from anemia to chronic dehydration to a basic inability to get out of bed. Nieman was both troubled and fascinated by these tales. Their symptoms all seemed to point to overtraining syndrome, and he’s been looking into the root causes of the condition ever since. Nieman, like other specialists in sports medicine, was aware of OTS back then, but with so few documented cases there were effectively no studies to review. The earliest known scientific reference to OTS was made by a researcher and athlete named Robert Tait McKenzie, who noted in his 1909 book, Exercise in Education and Medicine, an acute exhaustion and “slow poisoning of the nervous system which could last weeks or even months.” Decades later, renowned South African exercise-science professor Timothy Noakes wrote in detail about the condition in The Lore of Running. Published in 1985, it’s one of the few books athletes with OTS have as a reference. The runners Noakes examined had pushed themselves to a point at which their bodies—and, more perplexingly, their minds—had simply stopped responding. As a result, they suffered everything from “generalized fatigue” and “recurrent headaches” to “an inability to relax, listlessness,” and “the swelling of lymph glands.” Alberto Salazar. (Photo: Neal Preston/Corbis) Perhaps the most well-known case of OTS is that of American legend Alberto Salazar, now the head coach of the Nike Oregon Project. Between 1980 and 1984, Salazar set three American track records and won three New York City Marathons in a row. But he was also a self-described exercise addict, obsessed with the next race or workout and never satisfied with his victories. In 1984, his excessive training load caught up with him when he finished a disappointing 15th at the Los Angeles Olympic marathon. For the next ten years, plagued by respiratory infections and depression, Salazar struggled to figure out what had happened but found few answers. When he retired in 1998, he was barely able to complete runs longer than 30 minutes. Salazar pushed himself too hard, but his approach was rooted in science. Humans evolved to adapt to rising stress levels, which makes gradually increasing training load one of the most effective ways to achieve better results. It’s the reason marathon runners condition themselves with incrementally harder weeks followed by intervals of rest. This approach, known as periodization, often leads to overtraining—the routine muscle soreness and fatigue experienced by many athletes who endure a long season or a hard push for a big race. By some estimates, around 60 percent of elite runners will experience some degree of overtraining in the course of their athletic careers, but they re-cover quickly with strategic downtime. Overtraining syndrome is what happens when the body never gets that rest. Through some combination of excessive exercise and inadequate recovery, athletes experience a severe shock to the parasympathetic nervous system, which controls the body’s inflammatory pathways. Under normal circumstances, when your body is stressed, your sympathetic nervous system kicks in to help you respond. Your heart races. Your pupils dilate. The blood rushes from your digestive system to organs needed for immediate survival. The parasympathetic system is the counterbalance, bringing the body back to a state of equilibrium. After a hard outing, your heart rate calms and blood returns to your extremities, restoring your body’s normal functions. For athletes with OTS, those balancing responses no longer occur. The parasympathetic system effectively goes haywire. “You climb and you climb and you climb, and your body adapts to bigger and bigger loads,” says Jeff Kreher, a physician at Massachusetts General Hospital and the author of one of the only comprehensive academic papers on OTS, published in Sports Health in 2012. “But there will come a point where you reach the pinnacle and stop positively adapting to stress and strain, and instead you start responding negatively.” The consequences of pushing past that point are different for every athlete, but OTS can affect everything from hormonal balance to neurological function. Some athletes describe mysterious pains, loss of appetite, and diminished libido. Others experience strange heart arrhythmias or a debilitating staleness in their legs. (One runner told me that for days on end he couldn’t get his heart rate below 130 beats per minute.) Researchers say that OTS can mimic a host of diseases, including leukemia. But the most common symptom described by athletes is simply an ineffable, confounding lack of ability. “It’s not fatigue,” Kreher clarifies. “If you’re pushing the limits of your body, you’re going to feel fatigued.” Instead, it’s what Nieman first encountered in those letters he received: the sudden, almost overnight disappearance of a runner’s elite endurance talents. For athletes experiencing OTS, this can be terrifying. Even worse, doctors can’t tell them if they’ll ever recover.