Over the years I have asked these questions many times. I rarely hear about sleep inversion before three years of illness, and almost always hear about it after ten years. Is this something that comes on slowly? Can someone create a new poll that includes age of onset up to over ten years, year by year, and the same for no onset?
For me in the early years post onset, I was still working so I had no choice but to leave the house at 8am and keep going through the day, also I had 'hypersomnia' rather than 'hyposonia' so was sleeping every free moment, so if you are sleeping twelve or more hours a day, using every free moment for sleep, would you know if you had sleep inversion or not?
However I agree that studying the changes in sleep patterns over the course of our disease is important. Personally I find that hypersomnia is a feature of the onset and major relapses in my ME, but hyposomnia or insomnia on an ongoing basis is a feature of PEM or crashes.
Having said that when I have kept detailed activity records, though there have been periods of increased sleeping, if I allow myself to nap, when my sleep patterns are disturbed, I am still getting 7 or 8 hours a day sleep, just not necessarily in one go or at night.
What ideally are the dimensions we would need to measure to understand variation in sleep between individuals and within individuals over time:
- Total duration of sleep
- Pattern of sleep
- Types of sleep (deep, REM, etc)
- Refreshingness of sleep
- Activity context (what we are doing when not sleeping or trying to sleep)
- ?
It has often puzzled me that very occasionally I can wake feeling well, feeling I have had a good refreshing night's sleep. But I have no idea what happened to mark those occasions as different. I used jump out of bed taking this as a signal to attempt all the things currently on the to do list, invariably a mistake. Now I just enjoy the moment, know it will not last.
More generally now I feel 'worse' when I wake up and in a morning it takes several hours to get going.
I have a cat with a very strong devotion to her circadian rhythms, and so I have to feed her between 8 and 9am every morning. At the same time I bring in the milk (still have deliveries here) and take the cat into the garden as she is blind so needs monitoring outside. At present (last year or so), when I go back to bed I feel very cold (regardless of the actual temperature), rather like the feeling I would have got, pre ME, when getting up in the middle of the night to go on a journey. It will take a while to warm up, and I need a couple of hours rest or even a nap before trying to do anything else.