The name of a particular hour has ZERO connection to that hour's use. You body doesn't know if an hour is called noon or 5:00. It only cares in relation to the position of the sun and the length of the daylight hours.

If people stay on DST and it turns out that starting the day an hour later is more beneficial, then life will simply gradually adjust.

Tell that to the chronobiologists and sleep researchers and their peer-reviewed papers, I'm just the messenger.

You wake and sleep according to the artificial clock, but your body operates (chemically) on the amount of sun light that is available, and the discrepancy between the sun clock and the social clock, is where the health effects come in:

> For example, New York’s social clock closely matches the sun clock in winter during Standard Time: when the social clock says it is noon, it is very close to midday, the sun’s highest point in the sky. During DST, however, New York’s social clock shows noon when it is only 1100 h by the sun clock. People who have to get up at 0600 h by the sun clock in winter have to get up at 0500 h by the sun clock under DST, despite the social clock showing 0600 h. Essentially, they have to go to work in 1 time zone further to the east. This means that people in Chicago have to work during the office hours of New York, and people in Berlin have the office hours of St. Petersburg. Instead of seeing DST as working according to one time zone to the east, one can also think of it as people’s body clocks being pushed further west within their time zone (or social clock). Since the body clock follows the sun clock, these changes can affect our health.

* https://journals.sagepub.com/doi/full/10.1177/07487304198541...

> An understanding of time zones is essential for appreciating the effects of DST because switching to DST is nothing else but assigning the respective location to one time zone further east. This switch increases the discrepancy between the sun clock and the social clock by 1 h. This means that for Galicia [Spain] during summer, it is only 9:30 am by the sun clock when social clock claims noon, since they now have to live according to the hour-meridian that runs roughly through St. Petersburg [Russia].

* https://www.frontiersin.org/articles/10.3389/fphys.2019.0094...

> It helps with circadian rhythms. I seem to post this for every DST story, so I might as well continue the tradition:

All these arguments against a timezone change, removing the shifting to/from DST, etc are predicated on the assumption that the times that schools, work places, restaurants, public amenities, etc open and close through the year are not allowed to change.

This seems to be a surreptitious strawman argument against TZ/DST changes, as there's no legal or regulatory reasons to prevent any of these institutions changing their hours of operation.

The assumption is most of them won't change their hours. Because most of them don't. With or without DST.

Which of those sources say solar noon matters more than light exposure just before or after sleep?

> An understanding of time zones is essential for appreciating the effects of DST because switching to DST is nothing else but assigning the respective location to one time zone further east. This switch increases the discrepancy between the sun clock and the social clock by 1 h. This means that for Galicia [Spain] during summer, it is only 9:30 am by the sun clock when social clock claims noon, since they now have to live according to the hour-meridian that runs roughly through St. Petersburg [Russia].

* https://www.frontiersin.org/articles/10.3389/fphys.2019.0094...

> For example, New York’s social clock closely matches the sun clock in winter during Standard Time: when the social clock says it is noon, it is very close to midday, the sun’s highest point in the sky. During DST, however, New York’s social clock shows noon when it is only 1100 h by the sun clock. People who have to get up at 0600 h by the sun clock in winter have to get up at 0500 h by the sun clock under DST, despite the social clock showing 0600 h. Essentially, they have to go to work in 1 time zone further to the east. This means that people in Chicago have to work during the office hours of New York, and people in Berlin have the office hours of St. Petersburg. Instead of seeing DST as working according to one time zone to the east, one can also think of it as people’s body clocks being pushed further west within their time zone (or social clock). Since the body clock follows the sun clock, these changes can affect our health.

* https://journals.sagepub.com/doi/full/10.1177/07487304198541...

Those quotes just use social noon as an example. They don't say circadian rhythms are especially sensitive to solar noon.

Or you could simply read the article. Ctrl-F "circ" is handy:

> Although DST has always been a political issue, we need to discuss the biology associated with these decisions because the circadian clock plays a crucial role in how the outcome of these discussions potentially impacts our health and performance. Here, we give the necessary background to understand how the circadian clock, the social clock, the sun clock, time zones, and DST interact.

* https://www.frontiersin.org/articles/10.3389/fphys.2019.0094...

That quote doesn't mention solar noon at all.

I've read about chronobiology. It's well established light exposure just before and after sleep are the primary zeitgebers. I think it's fair you support your claim instead of expecting everyone else to read several thousand words looking for something probably not there.