Is ME stable?
M.E. is not a stable illness. One can probably observe people with some illnesses carefully for an hour or so and collect a lot of good information about what they can and can‟t do, how severe their illness is, and what their usual symptoms are from day to day, and so on. However M.E. is not one of those illnesses.
Observing the average M.E. sufferer for an hour -- or even a week or more -- will not necessarily give an accurate indication of their usual activity level because the severity of M.E. can wax and wane throughout the month, week, day and even hour. Also, people with M.E. can sometimes operate significantly above their actual illness level for short periods of time thanks to surges of adrenaline -- albeit at the cost of severe and prolonged worsening of the illness afterward. Relapses and worsening of symptoms are also very often also significantly delayed (there may be both an acute AND a delayed reaction).
M.E. is not stable from one hour, day, week or month to the next. It is the combination of the chronicity, the dysfunctions, and the instability, the lack of dependability of these functions, that creates the high level of disability in M.E.
Please see the HFME site for more information.