Jet lag before jets?

[Francis_Vaughan]

@CookingWithGas

The difference with shift work is that the sun doesn’t change. The change in sunlight when you travel is what cues your body to change its rhythm. With shift work, it’s a lot harder on your body.

In essence both are a matter of displacing your circadian rhythm. Bright light provides a forcing of the inbuilt clock.
Humans naturally have a clock that runs closer to 23 hours, and a bright enough light at blue wavelengths followed by dark triggers the reset.
Jet lag is countered with getting out in the sunlight and also by observing the sunset, which provides the key trigger for sleep. You can push the period long to push it back into sync, but it won’t go short.

Shift workers can try the same tricks. But a lifetime of switching shifts is really rough. No sooner are they aligned with one time regime than they get rostered onto a different one. At least putting the order of shifts so that their internal clock is running forwards makes the impost easier, but the other direction is still a common thing.

Shift workers circadian rhythms do slide to align with the shifts. Even if it is dark outside, working under artificial light wide awake is enough. It isn’t the shift that is the problem, it is the change in shift. That is pretty much identical to jet lag.

[Francis_Vaughan]

@Francis_Vaughan

have a clock that runs closer to 23 hours,

Oops. Missed the edit window before I noticed.
That should read 25 hours. Makes a huge difference.

[bump]

I have an intuitive notion that jet lag probably only kicks in when the difference is beyond the “normal” variation in sleep patterns we’d see- staying up a few hours later, or waking up a few hours later. Probably about 3 hours total, and probably around an hour’s worth a day. I mean, I’ve heard people gripe about the time change going to/from California by plane, but I can’t say I’ve ever heard anyone complain when taking a road trip.

So if you can keep that disruption in that window, you won’t suffer too much. But going to Europe by jet, you blow past that amount dramatically, and your internal clock needs to reset itself painfully.