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COVID-19 Has Put a Spotlight on Chronic Fatigue Syndrome

Chronic fatigue syndrome (also known as myalgic encephalomyelitis, or ME/CFS) has long puzzled the medical community. Because of that, many people suffering from this elusive syndrome have not found adequate answers or treatment for their condition. (In part because its very existence was debated!) While recommended treatments have changed drastically over the years, there is still no singular treatment that physicians can point to as a proven treatment for this syndrome. And now, due to the emergence of COVID-19 and “long COVID”, a spotlight is again shining on this condition.

Chronic Fatigue Syndrome

What is chronic fatigue syndrome?

Chronic fatigue syndrome is a cluster of symptoms including severe or debilitating fatigue that does not improve with rest, and is not caused by any other disease or syndrome (1, 2, 3). It is most common in young or middle-aged adults, although children, adolescents, and older adults can also experience it. Other symptoms are wide-ranging, including (1, 2, 3):

  • Trouble sleeping and/or poor sleep quality

  • Thinking and concentration problems

  • Dizziness

  • Headaches

  • Muscle and joint pain

  • Sore throat

  • Enlarged lymph nodes

  • Extreme exhaustion after physical or mental activity (also called post-exertional malaise)

  • Sensitivity to light, sound, or chemicals

  • Extreme thirst

  • Gastrointestinal disturbances (nausea, bloating, diarrhea, constipation)

  • Changed ability to complete daily tasks, school, or work

As more is understood about this syndrome, the criteria have been honed in. The new diagnostic criteria specifically includes “substantial impairment in activity that lasts six months or more and is accompanied by fatigue, post-exertional malaise (PEM), unrefreshing sleep, and either cognitive impairment or orthostatic intolerance” (3).

The CDC estimates that up to 2.5 million people may suffer from myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), with the possibility that up to 90% of those who suffer from this syndrome remain undiagnosed (1). Interestingly, ME/CFS is much more common in women, which aligns with the greater prevalence of other inflammation-related autoimmune diseases in females (1).

Unfortunately, many people with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) also have one or more underlying comorbidities (3). These comorbidities often overlap with the symptoms commonly found in ME/CFS, including fibromyalgia (muscle pain and poor sleep), postural orthostatic tachycardia syndrome (or POTS), IBS, gastroparesis, and vagal nerve dysfunction, to name a few. Even conditions such as depression, mast cell disorders, or Ehlers Danlos Syndrome can occur alongside ME/CFS (3).

What causes this syndrome? What makes it so complex to diagnose and treat?

Since the cause of this syndrome is still unknown, it creates a very complex diagnosis process, as there is no singular test or even group of markers that can definitively point to ME/CFS. Because of that, it is quite difficult to diagnose chronic fatigue syndrome - so the process of determining that it is ME/CFS is also the process of testing for and ruling out all other conditions (2). Even so, there are a few theories on what may cause chronic fatigue syndrome (1):

  1. Infections (including various viral and bacterial infections). Many people recall that their first ME/CFS symptoms started right after developing an illness, especially an upper respiratory illness. About one-tenth of patients who develop Epstein Barr virus, Ross River Virus, or Coxiella Burnetii end up developing some ME/CFS symptoms - especially if they had more severe symptoms. Chronic tick-borne bacterial infections such as Lyme disease, Babesia, Bartonella, and Mycoplasma, as well as Mold illness top the list of potential contributors to CFS/ME.

  2. Changes in the immune system. Because ME/CFS shares characteristics with certain autoimmune diseases and is linked to inflammation, it has prompted study into cytokines, natural killer cells, and T cells. Changes in the number or activity of any of these cells will change the body’s ability to respond to stress, worsen the ability to fight infections, and alter the immune system’s response.

  3. Altered body chemistry due to stress. Physical or emotional stress is commonly reported before the first ME/CFS symptoms arise. Stress affects our whole body, especially the HPA-axis (hypothalamus, pituitary, and adrenal glands). This system controls our physical stress response and our hormones, which has body-wide consequences. If something affects the HPA axis, the immune system and inflammation regulation can be severely impacted.

  4. Changes in energy production. While studies are still being done to determine what biomarkers can reliably be used to test for chronic fatigue syndrome, it is clear that there are differences between healthy people and those with this syndrome. One of the most striking (and logical) differences is the way that their bodies obtain energy through its natural processes, which is commonly referred to as mitochondrial dysfunction when not working correctly.

  5. Genetics. Members of the same family have exhibited ME/CFS. While more study is needed, it is thought that both genetic and environmental factors can prompt the development of ME/CFS.


Many are considering if COVID-19 should be added to the list of infections that can cause ME/CFS. Some are even wondering if some of the long COVID cases are actually chronic fatigue syndrome, or if they exhibit similar physiological changes (4). There is a striking similarity between ME/CFS and long COVID symptoms. In fact, the only common symptoms that long COVID sufferers report that those with ME/CFS don’t are rash, hair loss, and loss of smell or taste (5, 6). Even with their similarities, if there isn't a link between the two syndromes in terms of biology, there is an interconnectedness in terms of healthcare.

Just as ME/CFS was written off as a symptom of psychological or fitness-related issues, long COVID was also initially ignored. Often, those suffering from these syndromes receive normal test results, and since there is often very little physical evidence that someone is suffering, these patients have sadly often not received the care that they need (1, 4). The go-to treatment options for many years for ME/CFS have included either psychotherapy, including cognitive-behavioral therapy (CBT), or graded exercise therapy (1, 3, 4). While CBT can help these patients mentally cope with their illness, it has not been proven to help reverse the physical symptoms. Studies show that exercise therapy can harm certain patients with chronic fatigue, though in moderate amounts it may be helpful for others (1, 3, 4, 7).

While one proven treatment option is not yet available for either ME/CFS or long COVID, the rising number of cases will hopefully prompt more study and give physicians a greater ability to help their patients. In the meantime, there are a number of treatment options that can help reduce symptoms for ME/CFS (and long COVID) patients.

What treatment options are available? How can functional medicine help?

Because symptoms and symptom severity vary based on each patient, an individualized approach is necessary in order to bring relief - and this is where functional medicine can shine. Functional medicine clinics (such as Temecula Center of Integrative Medicine) focus on treating each person individually, approaching care with an understanding that each person’s health history is different and needs unique care. Functional medicine also seeks to address the root cause(s) of each problem, not simply address symptoms.

For something as complex (and without verifiable cause or diagnosis) as chronic fatigue syndrome that largely requires symptom management, functional medicine can still bring great relief. Because functional physicians seek to address the root causes of these symptoms, they can work with you to create a treatment plan to make sure that your systems are all as supported and healthy as possible to alleviate your body’s energy expenditure and reduce symptom severity.

We can partner with you to establish healthy sleep patterns that support restorative sleep. For digestive issues, we have found that a combination of adjusting diet, introducing probiotics, and supplementing with certain herbs and other natural supplements can heal the gut and reduce symptoms. Diet can also impact brain health, memory, and concentration, and even the HPA axis and hormones.

While diet can also affect muscle and joint pain, some of our regenerative therapies may offer even greater relief. Stem cell therapy, pulsed electromagnetic field therapy, and platelet-rich plasma therapy can all support the body’s natural healing processes, reducing pain, inflammation, and overall energy expenditure.

For those that can tolerate exercise, we can partner together to create a manageable plan to keep your body healthy, without causing huge crashes or overextending your energy. For those that can’t tolerate much physical or mental activity, we will work together to come up with a very gentle and achievable plan to help you feel better, more active, and more engaged.

If you are experiencing chronic symptoms, please reach out!

All of the treatment options listed above are available at our clinic, as well as many others that may be specifically helpful to your unique case of ME/CFS (or long COVID). If you are suffering from unexplained fatigue or any of the symptoms above, please reach out! It would be our joy to partner with you to help you heal, improve, and return to better health.


Jonathan Vellinga, M.D.

Jonathan Vellinga, MD is an Internal Medicine practitioner with a broad interest in medicine. He graduated Summa cum laude from Weber State University in Clinical Laboratory Sciences and completed his medical degree from the Medical College of Wisconsin.​

Upon graduation from medical school, he completed his Internal Medicine residency at the University of Michigan. Dr. Vellinga is board-certified with the American Board of Internal Medicine and a member of the Institute for Functional Medicine.




  1. Centers for Disease Control and Prevention. (2021, January 27). What is ME/CFS? Centers for Disease Control and Prevention.,is%20not%20improved%20by%20rest.

  2. Mayo Foundation for Medical Education and Research. (2020, September 24). Chronic fatigue syndrome. Mayo Clinic.

  3. Department of Health. Myalgic Encephalomyelitis ("Chronic Fatigue Syndrome"). (n.d.).

  4. Tuller, D., & Lubet, S. (2020, November 17). New guidelines reject useless chronic fatigue syndrome treatments. STAT.

  5. Huang, C., Huang, L., Wang, Y., Li, X., Ren, L., Gu, X., … Cao, B. (2021). 6-month consequences of COVID-19 in patients discharged from hospital: a cohort study. The Lancet, 397(10270), 220–232.

  6. Mayo Foundation for Medical Education and Research. (2020, November 17). COVID-19 (coronavirus): Long-term effects. Mayo Clinic.

  7. UpToDate. (n.d.).


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