That's quite an old picture, but it relates to the (soapbox) topic of the day.
I am lucky to be (for the moment at least!) earning most of my income at home writing. It's not just for mental reasons that it's easier. Some days I do several hours of work laying down. It's very common for me to research laying on my side and then compose paragraphs in my mind while lying very still on my back. After a while, I will sit up in and type quite a bit in a short time. If it appears that I spend half an hour immobile and then half an hour writing furiously... well, often I have been working the whole time, and far more efficiently than if I forced myself to sit up at the computer.
I imagine there are people here and there who have been diagnosed with chronic fatigue, or migraines perhaps, who have low muscle tone in their necks. For me, it's not bad enough to be a migraine -- the discomfort just toes the line between tiredness and headache -- but when I was a child, I called it a headache... and I was ignored. I remember that when I started morning kindergarten, I complained of daily headaches. It was because my teacher got after me when I rested my head on the desk, and my neck simply did not want to hold head up for three hours at a stretch.
I still feel better physically when I don't have to go too many hour at a stretch with my head unsupported. I even suspect the neck issue plays some role in the body ache issues I get sometimes -- like maybe it adds a bit of physical stress and brings my endurance down. I've always (when I've had the option) done a fair amount of my mental work lying down... especially the composition stage of writing. I have a great verbal memory, so I can do that! Yet to display so much of what looks like immobility... I imagine that has contributed at times to people seeing me as less mentally capable than I am.