Scrutable

I read an article the other day which points to evidence of quite large sleep deficits and other health detriments among people who live on the western side of timezones, in comparison to those who live on the eastern side of timezones, in the US.

Living at the western end of a timezone would be like having your clock almost an hour ahead of people who live in the west. So that tends to suggest that setting your clock further ahead is bad for you. In other words, daylight saving is bad for us, as the article suggested.

I like my long summer evenings. But the article suggested if I like long evenings, then I can always get up earlier. Though in fact what the experiment shows is that people cannot so easily set their own timetables, being social animals, and many of us feel the necessity to align our actions to social devised timetables. And that actually, getting up earlier is bad for you, so perhaps don't suggest it.

The blue light of the morning is particularly important, it seems, that we should be asleep and wake up to it. When I had to regularly get up in the dark in the darker half of the year, I used to use a sunrise simulator alarm clock, but only for half the year when I was waking in the dark. It doesn't work for everyone. But I found it worked for me. I was no longer tired all day, and was able to go to sleep at the 10pm in the evening to get my 8 hrs.

The research suggests that long evenings are also bad for us in making it hard for us to go to sleep. Certainly when I was getting up early and wanted to go to sleep at 10pm, it was annoying that it wasn't dark enough yet for a few weeks around the solstice. I found it harder to go to sleep at that time of year. But where I live, that's only a short period. Further north, you will suffer that if you have daylight saving or not.

I'm not sure how well these results would transfer to those of us who live at higher latitudes than most Americans, though, as that does produce a different light experience from them.

Well, if you live in a climate that isn't particularly warm, there is at least comfort in the daylight lasting longer. Especially when at the other end of the spectrum it feels dark pretty much all the time in winter. That's my very unscientific personal feeling about it anyway.

This campaign feels that permanent daylight saving would be good for us, which I understood to be quite a widespread view. I suspect there are numerous factors to be unpicked to understand why your source comes to a different conclusion…

It's pretty well established that shift work has serious adverse health impacts, so it wouldn't be a surprise that changing time zones regularly would as well, to a much lesser extent, quite apart from being unpleasant. So ISTM that you would need to have a pretty good reason to mandate regular changes.

Cultural time is significantly offset from solar time. By that I mean that, for example, "night" is legally defined as 23:00 to 07:00 in the EU for noise control purposes, and those are the typical hours that people are expected to be sleeping by society at large. This means that cultural midday is at 15:00 local time, three hours (winter) or two hours (summer) later than solar midday. It is not obvious to me that this is an efficient use of daylight, though all this stuff depends on latitude and time of year.

That said, many people can partly decouple personal time from cultural time, at least by the couple of hours necessary to make the best use of daylight. Many (though by no means all) jobs have flexible working hours, some evening leisure activities can be time-shifted (I'm mainly thinking of watching TV there TBH; the engrained tradition of evening activities such as theatres starting at 19:30 rather goes against that though), so maybe it's not too impractical to have waking hours of 06:00 to 10:00, say, which more closely aligns with solar time.