This is nothing but hysteric horseshit, but I will make this observation.
For many years, I drove to work in the morning and always had to readjust my rear view mirror, and then in the evening going home, had to readjust it again. Repeating this every work day.
It was years before the answer dawned on my after reading an article on what happens to the body at night while you sleep. In effect, the fluid around one’s spine can collect overnight and actually end up stretching the spine. IOW, you can actually be taller in the morning than the afternoon.
In my case, measurably so because of the rear view mirror adjustments required.
weight and temperature of the car also contribute to sinking in your chair
Back in the late 60's when my dad was a Detroit police officer, there used to be a height requirement in order to get on the force.
There was an Asian guy who repeatedly failed the initial physical because he was just below the height requirement.
Finally one day he actually had his friends carry him in on a stretcher, straight from his bed, and he passed........LOL! That's a true story too......
I had a job that required me to be standing and walking for about nine hours. I never took breaks or lunch. I would always have to adjust the mirror down before driving home. I knew it was because my spine compressed due to all the standing, more so than when I had desk jobs.