[fastball]

I think all of this is overemphasizing how much we are subconsciously "training" our bodies to do anything.

As with most human behavior studies, I have yet to see a sleep study that managed to satisfactorily demonstrate causality in place of correlation when it comes to working in bed ruining your quality of sleep.

In this particular case, you could imagine that people who work from their bed tend to be on screens in their bed until just before bedtime, causing them to be more "wired" than people who have a dedicated office space and avoid screens in their bed entirely.