A concern of taking a week off from running is that you may lose the fitness results you have obtained from your program.
The losses you feel are negligible, whereas the benefits could be significant. If you have sustained an injury that requires bed rest, the losses you incur may be as much as 10 percent, but that is a worst-case scenario. Depending on how long you have been training and your fitness level, your ability to rebound after time off will be quick. Your body periodically needs a week off, so allow yourself this luxury.