Remember all those admonitions about turning off your devices at night?  Like 30 minutes prior to going to sleep?

Yeah, they’re about as accurate as all those other warnings do-gooders want to impose on our lives.

It turns out that short bursts of light exposure (that does not mean leaving your TV on all night long- as I do) don’t disrupt our internal clock or our sleep routines.  (However, it may make it harder to fall back to sleep instantly.  We await that data.)   Our internal clock is found within the hypothalamus in the suprachiasmatic nucleus (SCN).

The SCN is connected to the optic nerve, so it’s not surprising that light information is collected at the SCN.  And, that sets the pacemaker for our circadian rhythm.  Knowing this, Dr. Tiffany Schmidt of Northwestern (along with Dr. A.C. Rupp, S. Hattar, C.M. Altimus, D.C. Fernandez, and M. Richardson (all of Johns Hopkins) plus F. Turek, and M. Ren (Northwestern)) bred mice with light-sensitive nerve cells that only communicated with the SCN.   Then they exposed the mice to short bursts of light.

Yes, I know there is a big difference between mice and humans.  Mice are nocturnal- so light exposure should make them want to go to sleep.  Instead, as the researchers published in eLife, the mice resumed their normal activities.  Their body temperature matched the normal circadian rhythm pattern.

The authors presume this means there is a different neural pathway when there’s long periods of light exposure, compared to the short bursts.  Otherwise, even short bursts of light should interfere with our circadian rhythms.

So, while I don’t condone your need to check your texts at various times during the night, it won’t leave your permanently disfigured.  (Just connected at the hip to your smartphone!)

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