Two years after breaking my leg in a freak running accident, I was logging up to 100 miles a week on the treadmill in preparation for a 36-hour adventure race. A veteran of 15 marathons and countless other athletic events, I was in peak physical shape. Or so I thought—until one Sunday morning when I could barely lift my arms. After years of lifting weights, I was too tired to lift the laundry basket. My own fitness, it seemed, had felled me. Was it overtraining? Had I pushed so far beyond my limits that my body could no longer keep up?
“Anyone who does endurance sports plays with the concept of overreaching,” says Jeffrey B. Kreher, a sports medicine specialist at Massachusetts General Hospital. “But overtraining is when the ability to tolerate stress is greatly diminished for whatever reason. The homeostasis of the body has reached its tipping point.” Kreher and fellow physician Jennifer Schwartz, now at Beth Israel Deaconess Medical Center, published a comprehensive review of the condition—“Overtraining Syndrome: A Practical Guide”—in 2012 in Sports Health.
In practice, overtraining can be hard to diagnose. Among the first signs are performance plateaus or declines. Resting heart rates can shift either up or down. Extreme fatigue and sore muscles set in. Ultimately overtraining disrupts the delicate balance of multiple systems, throwing off hormones, the immune system, behavior and mood. These effects can cause a confusingly broad range of possible symptoms—insomnia, irritability, anxiety, weight loss, anorexia, a loss of motivation, a lack of concentration and depression.
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No one knows what biological mechanism triggers the syndrome. One theory holds that it is caused by a breakdown of the hypothalamus, a brain structure that regulates many hormones, metabolic functions and the autonomic nervous system. “It's confounding,” Kreher says. “It's a retrospective diagnosis, and fatigue doesn't mean you have overtraining syndrome. Not all depression is overtraining. An individual's stress tolerance has many different influences.”
As Kreher and Schwartz point out in their review, trouble tends to begin when additional stressors appear in an athlete's life. “It might be excessive travel, it might be the pressure of the competition season, it might be monotony,” Kreher explains, illuminating one reason why my own endless treadmill miles had left me at a dead end. He notes that Olympic athletes, who are under tremendous pressure, can be especially vulnerable to overtraining. Some experts estimate that about 60 percent of elite runners and about 30 percent of elite swimmers overtrain at some point during their career.
It is something long-distance runner and former Olympian Ryan Hall (above) knows all too well. Once a favorite for this summer's Olympic Games, he withdrew in January because of extreme fatigue, following in the exhausted footsteps of famed triathletes Paula Newby-Fraser and Scott Tinley. When Hall called it quits, it was the end of a two-year battle with underperformance. Was it overtraining? Like me, he is not sure but comments: “If you want to run 2:04 for a marathon, you're going to have to train very, very long and intensely, and at some point that demand on your body will take its toll.” For Hall, the toll was mostly physical. “If I tried to run,” he says, “I felt like I weighed a million pounds and could hardly lift my legs.” For others, though, the distress is mainly mental.
The best treatment for overtraining is rest—which may sound easy: just snooze on the couch until your strength returns. But that prescription presents a challenge to athletes who have been conditioned for decades to train and compete. For elite athletes such as Hall, Kreher adds, it also raises an existential question of “Now what?” After cutting his running to three days a week, 30 minutes a session, and adding weight training to his routine, Hall is once again enjoying his sport, although he has retired from elite events. “My energy feels better than it felt my entire running career,” he reports. “It's a bummer not to be going to Rio, but I'm choosing to be grateful for the two Olympics I did get to go to.”
There are no evidence-based ways to prevent overtraining, Kreher says, but adding miles gradually and learning to be more resilient to stress—along with getting enough calories, hydration, sleep and carbohydrates—are key fitness fundamentals. Focusing on feelings can also help keep energy levels up. By recording their postworkout moods, for example, collegiate swimmers in a multicounty study reduced burnout by 10 percent, Kreher says. “If you do physical activity and feel joy, rejuvenation and health afterward, then that's appropriate,” he concludes. “If you feel it was work, then that's a sign to do something different.”
I've been following that sage advice myself lately, and after a long period of exhaustion, I am back running again.