From my personal experience and after hearing many similar stories from other weekend warriors and athletes, I wondered, Is “Delayed-onset Long Covid” is indeed a real phenomenon?
In my case, I had fully recovered from my first round of Long Covid in 2020 just in time to go elk hunting in the Colorado high country with my brother. Unfortunately, his “mild cold” turned out to be Covid-19. That is how I caught Covid-19 for the second time. Like my brother, for me it resulted in just a mild, but lingering cold. Three weeks later, I thought the infection was fully resolved and I undertook a fairly stenuous 2 day backpacking trip. We mostly bushwacked into some rugged mountainous country. It was glorious. But the day afterwards, I experienced severe fatigue. And second day after my backpacking trip, I was slammed with 8 typical Long Covid symptoms including brain fog, insomnia, head pressure, gut tightness/bloat as well as continuing severe fatigue. I did not even attempt to take a shower for 5 days. I now think this is a classic example of Delayed Onset Long Covid. Where apparent recovery from mild covid is followed by moderate to strenuous physical activity, which results in the sudden onset of multiple Long Covid symptoms. Another Long-hauler chacterized herself as an ultra-marthoner. She went for an “easy base training run”, really a 1 hour slow jog a few weeks after her acute Covid-19 infection. Afterwards, she had unusual fatigue. A week later, she repeated her easy 1 hour jog. After that, she developed multiple chronic Long Covid symptoms.
To date, I have had 189 long-haulers in my 2023 Long Covid Symptom survey report if they had a gap between their acute infection and the onset of their Long Covid symptoms. 34% did report a gap or a delay between their accute infection and the development of Long Covid.
I next attempted to assess if physical exercise might somehow precipitate the development of Long Covid symptoms.
Over 60% (pink, light green and red) reported some level of strenuous exercise or other strenuous activity in the week before they developed Long Covid symptoms. When I include “Walked or hiked for more than 2 hours”, another 17 percent reported moderate exercise (light blue and purple). Altogether, almost four out of every five respondents did moderate or strenuous exercise the week that they first developed their Long Covid symptoms. While, I don’t have a control group for comparison, that seems quite suspicious! Of course, other risk factors such as drinking too much alcohol, poor nutrition, and emotional stress may also contribute to the development of Delayed Onset Long Covid. Certainly, this is not the last word on the subject, but I do hope that this blog encourages others to investigate the Delayed Onset Long Covid phenomenon.
Let us assume for now that moderate and strenuous exercise is indeed a risk factor for the development of Long Covid. With regular waves of new SARS-CoV-2 strains circulating world-wide, how cautious should a weekend warrior be before resuming their prior exercise levels?
From my preliminary data, with 17 responses, it appears that waiting at least one month before resuming exercise may significantly reduce the risk. Unfortunately, Long Covid is a chronic dehabilitating condition with no treatment. The underlying root cause is still under active investigation and may be SARS-CoV-2 viral persistence. As such, I would suggest erroring on the side of caution and waiting a full 3 months before resuming even moderate physical exercise after a “mild” covid cold or other acute Covid infection. By this, I mean, do not do anything more strenuous than walking for one hour. One survey respondent did report developing their Long Covid symptoms 4 to 6 months later… hopefully this is a rare event. Of course, with the difficulties of accurately detecting covid infections and with a substantial percentage of asymptomatic infections, it may prove challenging to more accurately characterize Delayed Onset Long Covid.
Public health agencies, the CDC, and the medical community have been slow to recognize exercise as a possible Long Covid risk. The article below from New Zealand is a rare exception:
https://www.renews.co.nz/rushing-back-to-exercise-can-cause-long-covid/
Per Dr. Anna Brooks, young people who had been infected have said it may have been overexertion too soon in their recovery that may triggered their long Covid. “Many say they would never have pushed through had they known (the risk).”
Please consider sharing this blog with your friends and family. Get the word out about this currently unappreciated serious health risk.
If you have Long Covid, you may contribute to my unofficial (not IRB approved) exploratory research efforts by taking my Long Covid Symptom Survey. It also provides you with a way to track the severity of your Long Covid over time.
https://forms.gle/qXgDSVZTgTpoEW2E6
Sincerely,
Thomas Bunker PhD Sept 19th, 2023
P.S. My theory on how a sleepy bat virus could be behind this Delayed Onset phenomenon.