We all live by a seven-day week, but know very little about its remarkable story. This story, The Amazing 7) looks at the history of the seven day week, then chronobiology (the science of how time works with biology), and it goes on to an analysis of Biblical references to seven-day weeks. Here's another article: The Biological Shabbat Clock
I picked up on this topic from a Radio National talk on treating cancer. Apparently the effectiveness of cancer treatments is strongly linked to the day of the body's seven-day immune system cycle they are commenced on.
So here's my question: How do I measure which day of the weekly cycle I am on? When is my immune system at its peak? When at its trough?
Scientists have documented bona fide weekly fluctuations in human blood pressure, heart rate, blood chemistry, body temperature, kidney function, tooth development, urine chemistry and volume, stress hormones, various neurotransmitters, and the immune system.
Weekly rhythms appear easiest to detect when the body is under stress, such as when it is defending itself against a virus, bacterium, or other harmful intruder.
It also make sense of the concept of having a day of rest each week together as a community.