Long COVID and chronic fatigue: Is circadian disruption the driving force

Researchers have recently made several connections between a prolonged illness with COVID 19 called long COVID and chronic fatigue syndrome. If you’re unsure of what long COVID is, we did a 2-part interview with a woman going through it. You can check that out in part 1 and part 2.

Long COVID and chronic fatigue syndrome(ME/CFS) share a number of similarities. Similar symptoms include:

  • Fatigue
  • Exercise intolerance
  • Brain fog
  • Sleep disruption
  • Orthostatic intolerance

Another interesting similarity between long COVID and chronic fatigue syndrome is that ME/CFS often develops following viral illness. As a result, with potentially similar causes and symptoms, researchers have published a few papers linking the 2.

In the paradigm involving COVID-19, people experience a normal or even mild initial infection with COVID-19 that either goes away and then comes back or persists. They call this post-acute sequalae of COVID-19(PASC).

Moreover, in a subset of individuals, this sticks around for weeks(40-60%) or months(10-20%). When it persists for 6 months or more and there is no other underlying cause, it progresses to ME/CFS.

Long covid and chronic fatigue syndrome

The concerning thing here is that the initial infection can be mild, but you may still progress to ME/CFS. A recent paper posits that circadian disruption may be a common link driving this progression.

Circadian disruption, long covid and chronic fatigue

There are actually a couple of roles that circadian disruption may play in this link. First, the crushing fatigue from an initial COVID-19 infection promotes habits that disrupt circadian rhythms.

For example, sick people often get poor sleep, reduce their activity levels, and stay inside for prolonged periods of time. As someone who recently had COVID-19, I can tell you it can be pretty intense.

I never get sick, and when I do, it doesn’t change my behavior at all. COVID-19 was certainly different in that regard. I definitely cut my activity and had sleep disturbances. Furthermore, motivation was a problem and the brain fog was whack.

On the other hand, many viruses promote infection by disrupting circadian rhythms. SARS-CoV2 appears to promote viral replication by increasing a protein called transforming growth factor beta(TGFB). This protein plays a role in regulating circadian rhythms, which you can check out in the paper.

Consequently, 5 of 8 studies looking at ME/CFS find that people with that condition have elevated levels of TGFB. The hypothesis proposed in this paper states that people with pre-existing circadian disruption may be at increased susceptibility for progressing from PASC to ME/CFS.

Poor light exposure and/or hypoxia cause an uncoupling of the master and peripheral clocks. On its own, this may make you feel crummy, but not like hot garbage.

But, if combined with the a second hit of chronically elevated TGFB in PASC, this may progress to ME/CFS.

Progression from long covid to chronic fatigue syndrome

We’ve covered both how circadian disruption promotes ME/CFS in a blog you can check out here. We also covered a couple of people who corrected it in blogs here, & here.

My tangle with SARS-CoV2

Many of the people in my circadian program asked what I took or did to maintain mild illness. I’m sure many wondered if I took melatonin, vitamin C, quercetin, zinc, or what have you.

Truth be told, I really didn’t do anything other than what I generally do. I should mention I got a single dose of the J&J vaccine in July. But other than that, the only thing I “took” was collagen and creatine. However, that’s just what I normally take.

My diet remained high fiber/high protein. I did slash my physical activity for 3 days, but made sure I got outside in the yard to walk every day multiple times. I continued to work, but from home.

Light schedule stayed the same. Meal times and all that jazz stayed the same. Bedtime remained at 10pm, though I did sleep a little later.

I didn’t exercise. It was clear from my fitbit data that I was going through something stressful. Adding to that wouldn’t be a smart idea.

I slashed my daily steps to about 6000/day for 3 days then brought it back to 10,000 thereafter.

That was it, nothing fancy. All in all, pretty boring yet effective.


Overall, I felt good enough to hop on my Rogue Echo Bike to exercise after a week, though at a reduced pace. During my illness, I lost my taste/smell, had muscle aches experienced fatigue, and had brain fog.

One interesting thing that kind of shocked me was constipation that came on after all the other symptoms left. Not sure I’ve ever had constipation like that before, and it was interesting that it came on after the other symptoms went away.

I discussed why this likely happens in a blog you can check out here.

Currently, a bit over a month after infection, everything seems to be back to normal. No more symptoms, including constipation. Exercise capacity is back to normal. Sleep and stress management scores are all good.

Finally, my forced expiratory volume, a measure of lung function, is where it was pre-illness. The only thing I have to check out at this point is my A1c, which I’ll probably do soon.

Overall, my only concerns with COVID-19, which were long COVID and chronic fatigue syndrome, seem to be in the rearview mirror.

Note: Many asked which variant I had. I have no idea, they didn’t sequence my sample. If I were to guess, it was probably not Omicron.

Typically Omicron doesn’t cause loss of taste/smell, and that clearly happened with me. Sure, my illness was mild, but given that I am 45, healthy, and have a pretty healthy and consistent lifestyle, my case was likely to be mild regardless of which variant I had.

Now, I can just chill out and enjoy my super-breakthrough-immunity. 🙂

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