Well, truth is, I don't think it's a good idea to take a week off. I don't remember reading that in any thread, but I could have missed it.
There are two things about resting your body:
One is when you're working to build strength and muscle. What builds the muscle is the repair phase, not the working phase. So you *must* rest the muscles between workouts if you want to make progress. That doesn't mean not exercising at all, however. You can take a day off, or you can work one group of muscles one day and another group the next day (like doing arms and shoulders one day and legs the next, and so forth). The only group that I know of that you can work every day and still get optimal results are abs/core.
Two is constant cardio. Part A of this is that if you do the same cardio all the time, your body gets adapted to it and it's not as useful to you. If you go to the gym every day, do the exact same circuit of machines, do the exact same 30 mins on the elliptical, then your body is going to adjust to this, compensate for it, and eventually you won't make any progress. Part B of this is that even if you are mixing it up, at some point your body is going to get exhausted and overworked from not getting a day off. So you need to mix things up, even within the type of workout you do, and you need to take a day off now and then to let your body rest and recoup.
But.
Having said all of that, I've NEVER heard of anyone saying take a whole week off, and in fact I think taking a whole week off is hugely counter productive. A week is long enough to lose progress in both weight lifting and cardio, and will make it harder to go back when you do decide to continue.
2 days or 3 at most .. .but not a whole week. Ideally you'd work out anywhere from 5-8 days, then take a day off. Then 5-8 days, then a day off. That way you're rotating muscle groups, you're giving yourself a recovery day, and you're not staying away from it long enough to lose any progress.
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