ME/CFS and Long COVID: Your Brain May Be Trying to Protect You

Source: Hal Gatewood / Shutterstock.

Conditions like myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and more recently, long COVID, are the sources of significant confusion and contention among researchers, clinicians, and patients. Sometimes persistent physical symptoms which cannot be attributed to a clear biological cause are labelled “medically unexplained”. But perhaps this language says more about the limits of the traditional biomedical model than it says about these conditions.

A different way of understanding health is emerging, as supported by pioneering research in the field of psychoneuroimmunology (just rolls off the tongue, I know). According to this view, many of the chronic health conditions which are now the leading causes of illness and disability globally, may be best understood by studying the interconnections between different bodily systems.

These systems include the brain and nervous system, the immune system, the gut microbiome and the endocrine (hormonal) system, along with psychological and environmental factors.

Seen from this “systems” perspective on health, it makes less sense to seek a single biological cause for chronic illnesses, and more sense to look for the ways in which multiple systems interact. Building on this field of research, I introduced the idea that ME/CFS and long COVID can be helpfully understood as a potentially reversible state of imbalance in the entire organism, commonly following chronic stress, in previous posts.

In this post, I’d like to go further and explore why it is that the body enters into a state of imbalance which comes to feel terrifyingly rigid and intractable. If you are living with ME/CFS and long COVID, you may well be asking: Why has my body gone into shutdown mode?

Decline and Fall

To answer this question, a useful place to start is to ask: How did I get here? According to research, the three most common triggering factors for people who go on to develop ME/CFS are infections, stress or major life events, and exposure to toxins. I would say that each of these factors can be described as different forms of stress, in the broadest sense of the word. Indeed, the “father of stress theory”, Hans Selye, described stress simply as a response in the body to any demand for change.

Even though many people appear to become unwell with persistent symptoms after a viral infection or another insult to the body, this often appears to act as the straw that breaks the camel’s back. People have very commonly already been navigating extended periods of wider stress and strain — from relationship difficulties, and caring responsibilities to unrecognised and poorly supported neurodivergence or mental health difficulties.

Megan O’Rourke’s words in a New Yorker essay describe this trajectory well:

I got sick the way Hemingway says you go broke: “gradually and then suddenly”.

Some researchers have described the period running up to someone developing ME/CFS and long COVID, as a “prodromal” phase. In this period, in response to cumulative stressors, the body moves gradually from a state of relative balance, or homeostasis and towards greater and greater imbalance, or dyshomeostasis.

Over time, the wear and tear of cumulative stresses, or “allostatic load”, may begin to be expressed in what psychologists Gordon Asmundson and Steven Taylor call “body noise”. These are physical sensations which may start quietly, but grow much louder over time.

Dysregulation in the nervous and endocrine (hormonal) systems can give rise to a wide range of sensations familiar to ME/CFS and long COVID sufferers, including fatigue, pain, headaches, heart palpitations, altered breathing, increased sensitivity to light and sound, instability in body temperature, sweating, digestive difficulties, sleep difficulties, anxiety, brain fog and orthostatic intolerance (when symptoms become worse while standing upright).

A dysregulated immune system can give rise to what is sometimes called the “sickness response”, including fatigue, low mood, anxiety, reduced appetite, increased pain sensitivity, reduced interest in socialising, tender glands and a sore throat.

Some people with ME/CFS and long COVID may find themselves looking back at the less intense physical sensations they muddled through in the period before becoming ill as “early warning signs” that their stressful life circumstances were not sustainable. It is almost as if these “whispers” from the body go unheeded, and so must be amplified into the shouts and screams of more disabling symptoms in order to finally be heard.

A State of Emergency

Whether in the form of a viral infection, or something else, a final triggering event appears to prompt an existential crisis for the brain and body. The brain’s main job, after all, is to maintain balance in the body by weighing its resources in relation to the threats and demands in the world around us. In the face of one stress too many, it may be that the brain concludes that the body is fundamentally unable to meet the challenges facing it.

Chronic Illness Essential Reads

Cultivating Resilience in Your Chronically Ill Child

A Life Hijacked by Fatigue

Another way of saying this, in the words of one research study, is that there is a deterioration of allostatic self-efficacy. We might translate this as the brain losing confidence in its own ability to keep the body in balance.

The brain’s response to this crisis of confidence may then be to revert to a hyper-protective state. This is known as central sensitisation — a heightened state of sensitivity in the central nervous system. Researchers have suggested that central sensitisation may underlie multiple chronic health issues including ME/CFS, long COVID, some forms of persistent pain, fibromyalgia and irritable bowel syndrome. This is effectively where certain signals of danger and threat are amplified in the brain.

In this state of emergency, an alarm is sent by the brain to different parts of the body across various “homeostatic networks.” The brain is in two-way conversation with the immune system, and their shared response to perceived threats is the body’s “sickness response,” which we discussed earlier.

The symptoms of the sickness response — fatigue, pain, brain fog, dizziness, anxiety and low mood — are all useful in the short-term by prompting us to rest and recover from a viral infection or other insult to the body. But what happens when a hypersensitive brain continues to sound the danger alarm, even long after any infection has been defeated? The result may be the deeply unpleasant state of chronic fatigue and other symptoms experienced by people living with ME/CFS and long COVID.

In future posts, we will explore something crucial to understanding how this state of emergency in the brain and body may end up becoming locked in a vicious feedback loop. Namely, the brain is a predictive machine. The more it predicts danger, the more we may experience “protective” physical symptoms. The more we experience these symptoms as threatening, the more this danger signal is further magnified. This same understanding also opens up possibilities for reversing this cycle.