What’s wrong with this sentence:

“Good athletes train as much as they can, while great athletes train … and train … and train some more.”

Plenty, according to John Raglin, who studies “staleness” among elite athletes - the kind who were gunning for the gold in Atlanta. Raglin uses this refreshingly plain term to describe a persistent decline in performance.

Staleness can result from “high-volume, high-intensity training” for just about any endurance sport, including swimming, wrestling, weightlifting, basketball and cycling, Raglin says. Studies show that 60 to 64 percent of elite long-distance runners will go stale at some point during their careers.

Going stale

Staleness is a generalized condition whose major sign is a “pervasive loss of performance,” Raglin says, and often includes:

  • sleep disturbances
  • muscle soreness
  • perceptual changes (familiar routines seem harder than ever), and even
  • a “clinically significant depression that would benefit from some intervention.”

Who gets stale?

According to Raglin, about 5 to 15 percent of elite athletes can suffer staleness each year, and about 25 to 30 percent experience partial signs of the condition. Staleness can also bother roughly 30 percent of serious athletes at sub-Olympic levels, and a milder version of the syndrome can even bother recreational athletes who train seriously, he says.

R&R time

Among athletes with the highest motivation, staleness can become a trap, Raglin says. “They are very willing to train themselves into staleness, and they don’t recognize staleness for what it is.” Instead of slacking off, they typically respond to a drop in performance by training all the harder.

Part of the cure for staleness, Raglin says, is something that would please any couch potato: rest . Usually, a couple of weeks’ worth is enough, but he notes that “there are published cases where, after six months of rest, there are still hormonal disturbances caused by overtraining.” And in extreme cases, athletes have abandoned competition due to overtraining.

Raglin stresses that slacking off is not likely to harm performance. In fact, he says, “the performance gets better and better during the period of reduced activity. A lot of times they are afraid of backing off, but it’s not going to hurt their fitness level - generally it will only improve it.”

Immune to exercise?

In case you were still thinking that beating the pavement could only be beneficial, read on: Overtraining can also depress the body’s immune response. “With heavy training there tends to be a drop in the competence of the immune system,” Raglin says. “It’s very common to see infectious diseases at this level.”

How can exercise damage the immune response? Apparently by promoting the production of a hormone called cortisol. This so-called “stress hormone,” produced when the body is under stress, is known to suppress immune function. (Nevertheless, exercise, in reasonable amounts, can be a great stimulant to the immune system).

While staleness, depression, and sleeplessness can result from over-training, exercise more commonly induces a state of well-being that is often credited to endorphins. Endorphins - chemicals produced by the body that have a structure that’s similar to opiate compounds - usually get the credit for this state of well-being, but Raglin says other mechanisms must be involved as well. “We don’t know exactly why people feel better after exercise, since even if you [chemically] block the endorphins, you still see an improvement in mood.”

Reality check: Calling all Couch Potatoes

Let’s face it: For most of us, the big exercise problem is not avoiding overtraining and staleness, but getting the regular exercise that’s needed to keep the heart and circulatory system healthy.