The Wisdom of a Seventh Day Rest

Throughout the ages, human society has always seemed to allocate one day per week as a rest day. For Jews, it’s Saturday; for Moslems, Friday; and for Christians, Sunday. Even those who do not adhere to any specific religion seem to take it as a given that they work six days a week, and one of those days will be a “day off” from work. Is it a mere cultural belief, or is there truly wisdom behind this routine?
What does this have to do with the one-day rest per week? Perhaps we can look at the different aspects of our lives: