Blog readers note

Reading on a screen before bed might be killing you
Reading on a laptop or tablet can alter the way you think
Too much screen time damages the brain
Five things too much screen time does to your body
Before you start panicking and switching off your device, most of what is said in these articles refers to things we already knew – too much sitting about is bad for you, too much light from non ambient sources is bad for you, being too intensely interested in what you are doing is bad for sleeping, electrical devices near you damage your sleep, etc etc.  I am personally quite careful to keep things like sewing, gardening, driving, decorating quite far away from any functional computers so my time is divided between separate areas of the house.
This takes up quite a lot of room, and I am fortunate to be able to do this.  It will not always be the case, when my mother is not around any more I imagine that I will be struggling to pick up my long lost career, never mind afford somewhere that I can actually fit into.
A female friend from school, who coincidentally looked a bit like Daniel Vitalis’ identical twin, worked on a study with Stirling University in the 1990s, which was based on the premise that rural people are more affected by the full moon than city people.  Eventually the study narrowed down the reason for this to be the amount of electricity used in cities.  The brain tunes in with the electrical rhythm of the moon, other people or with the fridge, computer or other electrical device if they are in the same room, which is why people like me prefer to create at nighttime, when most people in the area have switched everything off.
Many artists and writers have noticed that they work much better at night.  I am not sure what implications that tapping away on a laptop might have for your writing, as opposed to avoiding devices, but even if we were not using computers, we would still be battling the light bulb.  Perhaps further studies on this are necessary.  In any case, when I told a few people about this, they were relieved to discover that they were not imagining it.  Stirling University has apparently not posted the study as it was conducted prior to the internet revolution, but I for one would be delighted if they would, since it makes some sense of a rather ‘woo’ sounding theory.
The physical implications of spending time in a chair are obvious, you will get a fat ass and a fat tummy if you do this too much.  The wrist and hand problems are another thing entirely, and you should be extremely mindful of making sure your ergonomics are better than mine (I am usually lying in bed covered in militant cats, which is no better for you.)
As I have previously mentioned, it is wise to leave your gadgets at home now and again, and if possible get away from your computer entirely once in a while.  It really does not matter if you do not see who has tweeted you for a week or more.  It does not matter how many likes you have on facebook, and it actually makes no difference to my figures whether I have a facebook following or not.  My book readers, in particular, tend to come from elsewhere.
If you are concerned about your abstract thinking, here are a few tests you can run
Free Aptitude Tests
Diagrammatic Reasoning Tests
Abstract reasoning test
If you are concerned about your emotional well being
Happiness test
Empathy test
Positive psychology test
And I am sure you can find some more by yourselves.  I find I self-regulate, on intellectual and creative as well as whether I am spending too much time with my computer.  I do not like to combine my care of mother with computer use, so again those things happen in separate rooms where possible. If I have been writing for a few weeks, I crave sewing, and vice versa, so despite my having been heavily involved with computers for nearly twenty years, apart from a couple of binge periods when life was not otherwise worth living, I have had pretty moderate exposure.  I do feel sorry for the younger generations who do not remember life without them.  As with the curse of the mobile phone, I am sure they feel naked without their connection, when the truth is that you are a lot more naked with it.