Only 22% of the world goes through the ritual of setting clocks back and forwards.

Driving around yesterday, I caught the snippet of an NPR conversation.

The researcher was expounding on the sensitivity of the human system to sleep deprivation. He made the following comment (from memory) - "Every year we run a natural experiment on 1.7 billion people. In the spring we impose the loss of one hour of sleep and in the fall we give them back an extra hour of sleep. It is called daylight savings time. In the spring, in the two weeks after losing an hour of sleep, the rate of heart attacks rises by 24% and in the fall they fall by 21%."

First - I had never thought of the quantification of people who experience daylight savings. It is primarily a feature of OECD countries in the higher and lower latitudes. There are some major outliers, though. China, which geographically covers probably four or five time zones, recognizes only a single national time zone and they do not use daylight savings time. Their clocks do not shift any time of the year, wherever they are in China.

At 1.7 billion people, only 22% of the worlds population experience the biannual ritual of the changing of the clocks. I have lived in seven countries on five continents and worked extensively in another couple of dozen at least. Had you asked me what percentage of the population experience daylight savings clock changing, I would have told you easily the majority. It is an interesting illustration of how even wide and varied experience can still foster blindness of reality.

Second - I don't know that the 24%/21% is quite as conclusive as it sounds initially but it sure is suggestive. The human system is a remarkable product of emergent order and in our modern era we are stress testing it in ways mother nature never anticipated.

Earlier this week I was talking with an Uber driver. I had asked whether he was from that area (downstate New York) and he answered that he was. That he was a local boy. He then framed it in a way I don't think I have ever heard before. He said something to the effect "I am so local I have never been out of this time zone. I was born and grew up here and I have been down to Florida and up to New England. But I have never been outside this time zone."

I thought it an interesting way to put it. A local boy who travelled but didn't travel east or west.

Which ties to an observation which, I think Jared Diamond made, that in general, geography, topography, and environments vary far more traveling north and south than they do going east and west and that therefore early trade patterns tended to be much more east-west than north-south. It was simply easier.