Taking a Week Off? Sudden 7-Day Exercise Cessation Perceived as a Strain by Highly Trained Athletes. Overtraining is the Culprit!

Did you ever decide to take a week off and felt like hell? Did you feel how the gym, a place of which, only two days before, you thought you would be happy not to see for at least a month, suddenly seemed to draw you in as a giant magnet? Yes? Then you are either an exercise addict or just a highly trained athlete (probably you are both), of whom a recent study (Zeller. 2011) published in the Israel Medical Journal reports that

exercise deprivation is associated with change in non-articular tenderness threshold and reduction in quality of life scores. 

I already hear the exercise junkie within you jubilating: "24/7, 365 days a year! That's the way to go. That's my way." Before you do fall for this misunderstanding, you'd better thing about possible underlying reasons for the sudden tenderness and the decrease in perceived overall health (-4pts out of 100) the 26 asymptomatic healthy athletes who regularly exercise 6.75 ± 3.65 hours a week reported after the 7 days intervention.
In fact, the scientists conclude that it is not the resting that fatigued them, but rather the constant exercise that prevented them from feeling their ever-increasing level of fatigue (keyword: overtraining):

[...] healthy individuals who have hypoactive function of the biological stress response systems unknowingly exercise regularly to augment the function of these systems. 

Aside from falling victim to the mainstream believe in the "more helps more"-principle, this almost pathological behavior, i.e. to blunt exhaustion by exhausting oneself even more, is unquestionably the central mechanism behind the commonly observed tendency of athletes, who are already severly overtrained, to 'naturally' ramp up training volume and/or intensity in order to achieve the short term satisfaction the increased nervous system stimulus provides. In the long run, however, this will inevitably lead to performance declines, total exhaustion, susceptibility to infections and injuries, and so on.

Bottom line: Take a week or two off every now and then. If you crash badly, you know it was about time ;-)