Exercise is an issue for every CFS patient, and there is no shortage of advice on whether and how to do it. On January 14th, the CDC hosted a conference call as part of its Patient Centered Outreach and Communication Activity (PCOCA) efforts. Dr. Nancy Klimas and Dr. Connie Sol presented their exercise advice for people with ME/CFS. I’ve seen some sharp criticism of the presentation, so I thought it would be helpful to compare their advice to the recommendations from Dr. Christopher Snell’s group at the Pacific Fatigue Lab. Dr. Snell and his collaborators (Staci Stevens, Todd Davenport, Mark Van Ness) have done the most work on exercise capacity in CFS, and published a conceptual model for safe exercise in 2010. You can learn more about their work in this webinar they gave last year.
Why Do It?
It’s common knowledge that exercise is an important part of preventing heart disease, diabetes, and osteoporosis. And I think most CFS patients would be eager to exercise if it did not make us sick. On Monday, Dr. Klimas said that deconditioning explains much of the dysautonomia seen in CFS. I think she may have overstated it because there are physically fit people who develop POTS, NMH or other orthostatic conditions, but deconditioning certainly wouldn’t help. Dr. Klimas described herself as the “perfect advocate to talk about exercise” because of her decades of research and clinical experience focused on biomarkers and immune function. She does not believe exercise is the only possible treatment for the disease (unlike proponents of the psychosocial model), but she also does not think it should be ignored.
I should note that while Drs. Klimas and Sol use exercise to provoke PEM so they can measure the gene expression cascade that follows, they have published no papers on exercise physiology in CFS. Snell and his group have published multiple papers on the topic, including a study that shows deconditioning is not the cause of PEM. Despite showing that there is metabolic dysfunction unique to CFS, Snell and many other experts recommend being as active as is safely tolerated. Stronger muscles will lead to less pain. Being as physical fit as possible will improve our chances with heart disease and other long-term consequences. If we can safely tolerate a certain kind or level of activity, we should do it. The emphasis must be on the word SAFE, and activity should be tailored to each individual patient’s capacity.
Identifying a Target Heart Rate
My articles on PEM and exercise explain the body’s energy systems and the importance of heart rate in detail. For purposes of this post, I can say that both Klimas and Snell agree that heart rate at the anaerobic threshold is the limit for safe activity in CFS. So how do we identify the correct heart rate?
Dr. Sol uses a single test in which the patient exercises to exhaustion. Multiple measurements help identify the heart rate at the anaerobic threshold, and then that heart rate is used to design an individualized exercise protocol. Dr. Snell and Staci Stevens use a two day maximum exercise test to do the same thing. That second test is critical because CFS patients’ metabolic function declines significantly after the first test. In my own case, my heart rate at the anaerobic threshold went from 105 on day one to 95 on day two. Under Sol’s system, 105 beats per minute would be my maximum heart rate, but that would be too high on any day that I was not well rested. My personal view is that by skipping the second test, Sol and Klimas are at risk for setting the safety limits too high for most patients.
Not everyone can take a two-day exercise test (for a variety of reasons), so there is a simple calculation for guessing at your heart rate at the AT. Klimas and Sol recommended: 220 minus your age times 60%. In my case, (220 – 44) x 60% = 105.6 bpm (matching my AT on day one). Stevens recommends 50%, or (220 – 44) x 50% = 88bpm (lower than my AT on day two). Here’s the problem with the calculation: a bedridden patient would not have the same limit as me (housebound) or a friend of mine (who can leave the house every day). We’re all sick with CFS; we all have metabolic dysfunction. But it’s unlikely that our heart rate limits are identical. Patients must be cautioned that the calculation is a guess only; careful experimentation is necessary to establish your safe level.
Defining Safe Activity
Both Sol and Stevens agree that the safe level of activity is the level that does not produce symptoms. Dr. Sol said that she knows she has prescribed the right level of activity when the patient reports that he/she feels no difference. Stevens has said that any symptom flare that lasts more than a few hours is too much and that activity must be scaled back.
What qualifies as exercise? Both Sol and Stevens agree that activities of daily living should be seen as exercise. The effort required to cook a meal or shower can raise your heart rate too high, and may need to by modified to stay in the safe zone. They both agree patients should examine the activities that make them tired, and try to adapt and pace those activities. Dr. Klimas said that these methods will lead to a more even, reliable supply of energy; Dr. Snell has said the same thing.
Beyond activities of daily living, Sol suggested yoga or non-weight bearing activities such as water exercises. She recommended starting with a minute or two of activity followed by a few minutes of rest, repeated five times once a week to start. In contrast, Stevens recommends a more modest starting point of stretching and range of motion exercises. Patients should advance to low intensity, short duration activity only if the stretching is well tolerated. For Snell and Stevens, heart rate is not the only indicator of capacity. Patients must pay attention to their perceived level of effort, and avoid activities (or activity duration) that feels “somewhat hard.”
There is no question that there are CFS patients who are too sick to come to a lab and pedal a bike for eight minutes. Accordingly, these patients have not been studied for metabolic dysfunction and exercise capacity. Drs. Klimas and Sol made no comment on Monday about what these patients could or should do. I interviewed Staci Stevens as part of the research for my article on exercise, and based on her advice I wrote:
A bed bound patient may need assistance to turn in bed or complete basic activities such as showering, but heart rate biofeedback can help identify the appropriate pace and duration of these activities. Bed bound patients can also try deep diaphragmatic breathing, perhaps six deep breaths at a time. Deep breathing will lower heart rate, and also work the large muscles of the diaphragm. Severely ill patients might begin with passive stretching, where a physical therapist or caregiver moves the patient’s limbs slowly and carefully to gently stretch muscles and try to improve flexibility.
This must be done very cautiously. There is simply no published data that investigates the metabolic dysfunction in bedridden CFS patients or that explains what they can do safely. The cost of trial and error can be high, so patients should be very careful.
Reasonable and realistic expectations are an important part of any rehabilitation effort. Snell and his group describe the goal as being as active as possible within toleration, and hopefully this will lead to a more predictable energy supply (eliminating the push-crash cycle). In contrast, Dr. Klimas said on Monday that patients will show improvement if they follow the program, and that when they stay below the AT they feel “much better.” Then Dr. Klimas claimed that some patients have been able to return to work or athletics. This is an extraordinary claim, especially in the absence of published data. How impaired were these patients to start with? How long did they follow the program, and was the program standardized across patients? Did these patients show objective improvement on subsequent exercise testing? How long did their improvement last?
Personally, I was very surprised to hear Dr. Klimas make this claim. She is quite familiar with the severity of the disease, the dearth of treatments, and the danger of false hope. In my opinion, claiming that pacing with a heart rate monitor and slowly progressing exercise is curative in the absence of published data is misleading, at best. The notion that exercise will make us all better is pervasive and potentially harmful to patients. Show me the data.
There are many similarities between the advice of Klimas and Sol on the one hand and Snell and Stevens on the other. Both sides agree that patients should be as active as they can safely tolerate. They agree that activities of daily living should be seen as exercise. Both recommend using a heart rate monitor to pace activity by staying under the anaerobic threshold. Both recommend starting very slow with exercise, and avoiding exercise that increases symptoms.
There are also some differences. The two groups calculate the safe zone differently, with Klimas and Sol potentially setting limits higher than patients’ anaerobic thresholds. Klimas and Sol offered no advice to bedridden or other severely incapacitated patients, while Snell and Stevens offer at least a little guidance. Finally, Snell and Stevens do not suggest that their program is curative in any way. They suggest a cautious but realistic goal of eliminating the push-crash cycle. In contrast, Dr. Klimas was quite expansive in her claim that her program had helped some patients return to work.
Despite their differences, both groups give the same basic advice to CFS patients: use a heart rate monitor to help you recognize when you are doing too much; ensure adequate rest; be as active as you can without triggering symptom flares or post-exertional malaise. This is a good starting point, but I hope that one day we will have access to physical therapists and others trained to help us navigate these limits. From my own experience, trying to apply this expert advice on my own has been unnecessarily frustrating.