The Insanity workout program promises to transform your body in just 60 days. The intense, full-body exercises in this workout can do exactly that -- as long as you're physically prepared for such intense workouts, use proper form, eat properly, and stick with the program. So the decision to take a week off has two sides: On the one hand, it'll slow your progress toward the goal. On the other hand if you're sick, injured or have overtrained, taking some time off is the only sensible thing to do.
The obvious downside to taking a week off from the insanity workout is that it'll turn your 60-day goal into a 67-day goal. And if you're thinking of taking time off because you're psychologically intimidated by such intense workouts, getting started back up after the week's break could pose a serious hurdle. If you're struggling mentally, focusing on how far you've already come may help you stick with it on the days you're feeling intimidated or discouraged.
The Insanity workout includes one full day of rest and one lighter "recovery" day each week. If you're struggling physically, you may have good reason for taking even more time off. Symptoms such as excessive soreness, unusual gastrointestinal problems, sleep disturbances or an injury can signal overtraining -- in which case you really do need some time off to recover. And of course if you're ill, give your body all the recovery time it needs.