how is like not to bath for 1 week?

It's incredibly gross. I did that once because I had no choice. When I was 18 I had to do military training. Part of that training was a 6 week long bush warfare course. During that time we had to spend 1 week in the bush without soap or toothpaste. This was because if the "enemy" is downwind from you in the bush then they can smell your soap or toothpaste.

After that one week having a shower was the best thing ever.