In late December 1989 I had an unspecified flu-like illness. I had a fairly high fever (101-102, don't remember exactly). I had chills along with body aches and other flu-like symptoms. We had just come back from an 4 week trip to India (visiting my husband's family) so, even though we were both on anti-malaria drugs, my husband mentioned malaria to the doctor just as a possibility (it wasn't).
After about a week I thought I had completely recovered. I went back to my normal work and exercise schedule in January 1990. But slowly I started to go downhill. My first symptoms were feeling lightheaded and dizzy. Then shortness of breath and increased heart rate just doing normal things like walking upstairs. Then PEM, aka, PENE, after working for a full day. I don't know what I called it at the time (didn't know about PEM) I just knew that I felt like crap.
So, I ramped back on my exercise, and took lots of sick days, but in spite of extra rest I kept going downhill. By early March (barely two months) I had gone from my normal exercise routine of 45 minutes on the stairmaster (remember those?) at level 8-9 to doing no exercise at all (stopped lifting weights, hiking, etc.). I felt exhausted just walking from my car to my office. This is one reason why I simply laugh when anyone suggests deconditioning as a cause.
By March 1990 I was taking a sick day every other day, and this wasn't going to work long term, so I had to go on full time medical leave. All my tests were normal so the doctors assured me that this was some kind of "post viral fatigue syndrome" which would completely resolve with rest. After some time on medical leave (about two months) I felt better so I returned to full time work. A month or two after that I started to exercise again. Then in the summer of 1991 the symptoms returned, along with new symptoms, and the time from initial symptoms to being too sick to work was much shorter (couple of weeks instead of couple of months). I went on another medical leave.
Leaving out lots of details, the short version of my story is lots of ups and downs (go out on medical leave, return to work,
repeat many times) until I finally had to go on long term disability in 2000.
So, my illness onset was not "I got sick one day and never recovered at all." But it was also not "I gradually got sick over a period of years." I had a definite illness onset but I was able to fight against the illness for a long time. Before I got sick, my idea of a fun day was to leave after work, drive to the Columbia River Gorge, do a 6 mile hike (approx 1500 ft elevation gain), then drive home by about 9 PM.
Whenever there are discussions about being limited to less than 50% of previous activity, I always think, does that mean that since I used to do a 10K run that a 50% reduction would mean I could
only do a 5K run?
At my worst, I would get up from the couch to open the front door for my husband and suddenly have to sit down immediately. Right there on the floor. (In hindsight I think that was partly due to the untreated orthostatic intolerance) At any rate, if that distance was about 10 feet then we're talking 0.03 % of my former activity level of a 10K race? (someone probably needs to check my math, LOL)
Whether fighting my symptoms was a "good thing" or a "bad thing" is a question I'll never be able to answer. At least from a psychological point of view I know that I did every single thing in my power to keep on working. I loved my job. Knowing that I tried everything I could do to keep working, even if it might have damaged my health, is actually some comfort to me. Yeah, probably too much work ethic, I know, but that's who I am (or was).