Phys Ed: Crash And Burnout

To understand the toll that overtraining can take on an athlete’s life, consider the competitive arc of Whitney Myers, a fifth-year senior and a world-class swimmer at the University of Arizona. In 2006, Myers won the women’s N.C.A.A. title in the 200- and 400-yard individual medleys and, to the surprise of almost everyone, won gold in the 200-meter individual medley at the Pan Pacific Championships. The accolades kept coming: Myers was named an all-American in several events and an N.C.A.A. Breakout Performer of the Year and swam for the United States national team. But barely a year later, she floundered badly at the 2007 long-course championships, making the finals in only one event. For weeks before that, her performance in practices had been miserable: slow times, inert form. “I remember standing behind the starting blocks at the pool and thinking, ‘I don’t want to be here,’ ” she says. “I felt terrible, mentally and physically.” While trying to build on her breakthrough season, she had pushed too hard. She had overtrained. She was, for a while at least, finished as a swimmer.

Though it seems innocuous, overtraining isn’t just a matter of having overdone things in a workout or two. It is, instead, a recognized illness (known formally as “overtraining syndrome” by the growing cadre of doctors and researchers who study it), similar in many physiological and psychological respects to chronic-fatigue syndrome and major depression, but exactly like neither. Overtraining strikes indiscriminately, felling both endurance and strength athletes, particularly the most hardworking and tenacious. By some estimates, up to 60 percent of competitive athletes overtrain at some point. A recent study of over 200 elite British athletes across a wide spectrum of sports found that more than 15 percent met the criteria for being overtrained. More ordinary types can succumb, too. “I work with a lot of runners and distance athletes,” says Ralph Reiff, the director of the St. Vincent Sports Performance Center in Indianapolis and a leading expert on the symptoms and treatment of overtraining. “In my experience, a large percentage of the people who train for 10Ks, half-marathons and marathons are overtrained by the time they reach the starting line. Same with cyclists and cross-country skiers. A very high percentage get into a state of fatigue that they just cannot get out of.”

Until recently, overtraining was a medical enigma. Scientists and physicians hadn’t understood much about the condition’s underlying causes or why it would strike one athlete but not his training mate. But in the past year, new research has begun to explain why hard training sometimes ends in illness and how we may soon be able to predict when someone is on the verge of overdoing it.

The most frustrating thing about overtraining is that it’s an outgrowth of optimum training. “You can avoid overtraining by undertraining,” says Bob Larsen, the co-coach of Team Running USA, “but then you don’t win medals.”

Intense, prolonged training causes significant trauma to muscles, but trauma, in the right amount, is actually a good thing. Immediately after a hard workout, there’s a rise in blood levels of CPK, an enzyme released from damaged tissues. The trauma also prompts the production of cytokines, which are inflammation-inducing proteins. Inflammation speeds blood flow to the sore muscles and aids in healing. In response to the inflamed muscles, the body releases cortisone, a stress-linked hormone that reduces swelling. When the levels of these various substances are in balance, the inflammation and soreness in muscles will last a day or two, after which the muscles should not only have recovered but be stronger than before.

That’s the theory behind “overreaching,” a training strategy followed by most competitive athletes today. “You push the body up to the breaking point,” Reiff says. “At least, that’s what you try to do.” Overreaching is often part of a months-long regimen that ends with tapering: doing only light workouts in the days before a big event. If all has gone well, athletes will, at that point, be at their physiological peak.

But all doesn’t always go well. “You expect a peak, but you get a slump,” Reiff says. Why? According to one hypothesis, constant training leads to overactive cytokines. These proteins may communicate with circulating blood cells and cause them to ramp up the production of chemicals that can inflame the whole body. Instead of being confined to the wounded muscle tissue, inflammation becomes systemic. This theory (hard to test, since no coach is likely to allow a scientist to induce overtraining in his athletes) may explain the wide range of symptoms often seen in overtrained athletes: mood changes, apathy, insomnia and fatigue. Overtrained athletes often lose weight, possibly because of decreased appetite, and they can have low levels of ferritin, a protein complex that helps store iron in the body. They can experience a rise in resting heart rate, which is one of the surest signs of overtraining, or have especially viscous blood. Some researchers believe this sludgy blood accounts for the odd heaviness in the legs that overtrained athletes report.

Genetics, not surprisingly, is thought to play a role in the onset and severity of overtraining. Research that is currently under way at Baylor University in Dallas, and funded by USA Track & Field, suggests that hard, competitive training of any kind can alter the ways in which a wide array of genes work. Genes of well-trained athletes are thought to encode proteins that prompt the body to produce chemicals that, in turn, increase the levels of certain enzymes and stimulate other processes necessary for creating speed and endurance. It’s an elegant cycle: the demands of the straining body activate genes that produce the means of making that body stronger, tougher and faster.

Baylor scientists have taken blood samples from elite American distance runners in an attempt to determine whether some genes become either exceptionally active or suddenly quiescent when an athlete nears his or her fitness limit. The irregular activity of these genes may be the cause of overtraining, or it may be that the genetic changes are only the first, microscopic symptom of its onset. If further research shows the same genes at work in those who are overtrained, blood tests may soon substitute for guesswork among coaches and athletes. “Right now, we use trial and error to get someone as fit as possible without going too far,” Larsen says. “It’s more art than science. It would be great if it became more science.”

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