The Science Behind Exercise Intolerance and Chronic Fatigue Syndrome

The Science Behind Exercise Intolerance and Chronic Fatigue Syndrome

The debate over the idea that exercise can help a patient with CFS, has caused many sufferers of this disease countless frustrations. As a patient myself, I can say that hearing a doctor claim that your symptoms will be better if you just push through the fatigue and begin to exercise regularly, is enough to make you want to scream.

Nobody tells a person with a broken leg, to just walk on it until it feels better. Or a person with lactose intolerance, to just drink milk until they don’t feel sick anymore. But for some reason, many doctors feel they need to tell patients with CFS that exercise will cure their fatigue, or the lack of exercise is what has caused it. It’s really infuriating.

The following are excerpts from an article about post-exertional malaise (fatigue after exercise or activity).

One thing patients and medical providers agree on is that CFS is characterized by post-exertional malaise, a term that often understates a “payback” that varies from escalation of widespread pain, to exhaustion requiring a recovery day in bed, to serious relapse of the entire CFS symptom complex: the cognitive dysfunction, flu-like achiness, fatigue, low grade fevers, lymph node tenderness and disturbed sleep patterns of weeks or months duration.

If you don’t have CFS, then you can not even begin to imagine the extent of these symptoms. But let me assure you as both a nurse and a patient, these symptoms are very real.

Have compassion for your patients, your family, or your friends with this condition. Living with Chronic Fatigue Syndrome is not easy, but it is a little easier when people in our lives are supportive. And quite frankly, not enough of you are. For more information about this, please see my post on empathy.

Post-exertional malaise has always been considered a defining feature of CFS, although we are still uncertain why it occurs (Fukuda). A recent genomics paper clearly demonstrated a difference, using gene array technology, between CFS patients and controls before and after exercise (Whistler).

This finding may be unique to CFS.

The CFS patients had almost a 20% drop in VO2 on Day 2 compared to normal, deconditioned controls who achieved the same VO2 on Day 1 and Day 2 of exercise testing. In another study, the same research team objectively demonstrated a decline in cognitive function in 20 CFS patients 30 minutes and 24 hours after a graded cardiopulmonary exercise test compared to pre-exercise levels, with no such observed change in the 20 age matched deconditioned controls (VanNess, unpublished manuscript).

A related concept is the idea that a “threshold” exists at which something pathologic happens in the body because of exercise or activity, and that exceeding the threshold causes post-exertional malaise. Knowing exactly what happens at the threshold, where the threshold is, and how we can raise the threshold are questions that have proven difficult to answer, at least in some patients.

This is a not a foreign concept in medicine.

A diabetic can develop life-threatening hypoglycemia from exercise. Exercise converts asymptomatic coronary artery disease to ischemia, infarction, and fatal arrhythmia. Certain asthmatics develop severe bronchospasm from exercise.

In some instances of CFS exercise can be helpful in moderation, but it is very important that each patient be evaluated based on their individual needs. What works for one person will not work for another, that is why understanding and patience by medical professionals is so important.

In each of these disorders, while potentially deadly, exercise is also an important therapeutic intervention. In each case, exercise is safe if:

The underlying condition is well defined and under good control,

A safe level and type of exercise are prescribed,

And the patient is meticulously educated regarding how to exercise and how to recognize signs that exercise should be limited.

In the absence of adequate information about CFS, we should prescribe exercise with the same cautious and attentive approach we might use if we had inadequate clinical information and treatments for our asthmatic, diabetic or cardiac patient. We can still utilize exercise therapeutically if we respect what we do not know, and utilize what we do know from research, clinical experience and the observations of our patients.

Patients with CFS who are unable to remain active become deconditioned, but their ability to tolerate exercise stress and raise the threshold may be impaired compared to normal individuals. Indeed, recent studies published by the CDC Computational Challenge teams suggest that CFS patients may have more difficulty than others recovering from common physical stressors, as measured by increased allostatic load (Maloney). It is possible that some stressors leave a mark or permanent injury in patients with CFS, as if their normal stress response and recovery mechanisms are dysregulated or chronically depleted.

It’s important to understand both the science of this condition, and the individuality of the patients. This is a medical problem, with symptoms that affect the whole person, which is why a holistic approach to treatment is needed.

In addition to physical deconditioning, there are many partially understood aspects of CFS, well established in the literature, that might contribute to an exercise threshold, the exceeding of which could result in pathologic injury. This might include:

Defects of oxidative metabolism,

Dysregulation of the autonomic nervous system and HPA-axis (CRH, cortisol and aldosterone),

Presence of chronic or latent reactivating infection,

Dysregulated immune or inflammatory systems (cytokine production, natural killer cell function, complement activation)

And other yet-to-be clarified processes.

An understanding of why these symptoms occur, is not as important as an acceptance of this condition as real.

It is not difficult to imagine an exercise or activity threshold in someone with CFS after which the body experiences physiologic injury that contributes to post-exertional malaise. It is not necessary to understand this before we respect it.

There is no doubt that my hundreds of patients who meet the CFS case definition exhibit a wide spectrum of exercise tolerance.

n On one end of the spectrum (perhaps a Fibromyalgia patient with metabolic syndrome who meets the CFS Case Definition), the response to graded exercise is satisfying and clinically helpful. These patients can gradually increase their strength and aerobic capacity with proper conditioning, resulting in weight loss, better energy, improved pain and fatigue. Some even recover a higher level of function, although the Fibromyalgia symptoms usually remain to some degree.

n On the opposite end of the exercise tolerance spectrum are certain CFS patients who invariably experience a severe relapse of symptoms after attempting to increase their physical activity, either immediately or within a few weeks. It seems that even the more healthy patients of this subset must reduce other activities in order to substitute and sustain a low level exercise regimen.

The point is that we don’t need to understand all aspects of CFS or even be able to objectively subset our patients to begin sensibly utilizing physical conditioning to improve their health. From the clinical standpoint, our patient population will always be heterogeneous. There will always be a spectrum of contributing factors, including primary etiology, stage, co-morbid conditions (including obesity and deconditioning), severity of pain and secondary relapse symptoms, age, plus a variety of personal skills, resources, motivation and discipline. It is possible to adapt exercise advice compassionately and intelligently to the individual situation.

The following are some ideas about how to help your CFS patients discover how they can best improve their physical conditioning, given their particular level or type of illness.

Don’t Call It “Exercise”

We all, patients and providers, have inflated perceptions about what the word exercise means. Instead of asking about exercise, try: “What are you able to do

…to keep your muscles from becoming weak?

…to keep your body moving?

…to stay strong and flexible?

…to work on physical conditioning?”

I hope this new information will be a step in the right direction toward the understanding and acceptance of Chronic Fatigue Syndrome. For more information you can read the full article from ProHealth “Chronic Fatigue Syndrome and the Exercise Conundrum“.

Also See:

Fighting Fatigue – Effects of Exercise in CFS

Tips on Healthy Living With Chronic Illness

You can see more informative videos about Chronic Fatigue Syndrome and Fibromyalgia at my video page.

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