By J. Mark VanNess, PhD,
Christopher R. Snell, PhD,
and Staci R. Stevens,
Drs. VanNess and Snell are professors with the Depart-ment of Sport Sciences
University of the Pacific. Ms. Stevens is an exercise physiologist and chair of the Workwell Foundation,
an organization specializing in helping people cope with chronic illness.
Since chronic fatigue syndrome (CFS) is characterized by debilitating malaise
and the inability
to perform physical activity, it is often assumed that patients should begin an exercise training regimen
to increase their ability to function. However, the ability to generate energy through aerobic energy
pathways appears to be dramatically impaired in CFS patients and post-exertional malaise can extend for
days. Because of this, aerobic-type exercise may be inadvisable for the CFS patient.
something of a problem, as the patientís inability to exercise leads to further deconditioning. Prac-titioners
are often contradictory concerning exercise for persons with CFS: some recommend aerobic exercise in an
effort to recondition the patient, while others decry any physical activity because of the negative impact
on their patients. This raises questions concerning the etiology of what is essentially a cycle of deconditioning
for CFS patients and what, if anything, can be done to reverse the worsening of symptoms many patients
have when they exercise.
There are a number of theories on why CFS patients are unable to
perform even the simplest of tasks without becoming fatigued. Several studies indicate moderately reduced
oxidative capacity in CFS patients, which may provide an important clue to the origins of this fatigue.1
Our own research has shown significantly lower exercise duration and peak oxygen consumption in
a subset of CFS patients positive for the RNase L enzyme compared to CFS patients negative for the enzyme.2
Presence of the RNase L enzyme is believed to be connected to an immune system dysfunction that may interrupt
energy production, reducing aerobic work capacity.3
Any reduction in aer-obic work function
due to impaired oxidative function may lead to an abnormal reliance on anaerobic energy pathways during
exercise. Therefore, what may be an aerobic exercise regimen for healthy individuals could actually be
an anaerobic activity for CFS patients.4
Even activities of daily living, like vacuuming,
may exceed the limited aerobic capacity of CFS patients. The rapid onset of fatigue and extended recovery
time following physical activity may be explained as an expected reaction to intense anaerobic activity.
research shows significantly impaired oxygen consumption levels (according to AMA guidelines) in persons
with CFS during treadmill exercise tests. Although the subjectsí volume of inspired air during exercise
is normal, the oxygen they were able to use from that air was diminished.5 These findings suggest that
exercise testing could be used to both diagnose and assess the level of disability in CFS patients.
possible solution to this problem may be to prescribe exercise for CFS patients with the acknowledgment
that performance will rely heavily on anaerobic metabolism. This means avoiding extended periods of aerobic
activity and alternating short periods of resistance exercise or stretching with frequent rest breaks.
exercise designed from this perspective aims to increase strength and improve flexibility rather than
reconditioning the aerobic system. Such a program would have the added goal of reducing muscle pain, improving
cognition and providing a sense of accomplishment and well-being.
If exercise is to prove beneficial
for CFS patients, it is important that the exercise prescription is one they can accomplish. This means
starting slowly, gradually increasing the intensity, and most important, allowing adequate time for recovery
between sessions. The following guidelines are intended as general recommendations for CFS patients without
other health conditions. It is advisable for patients to perform these exercises under the guidance of
a qualified physical therapist or exercise physiologist sensitive to the needs of patients with CFS.
Appropriate exercise for CFS patients is exercise
recover from. Therefore, the main goal of the program is not to develop aerobic exercise capacity, but
rather to increase the patientís ability to utilize anaerobic energy systems and then to recover in a
reasonable length of time.
important that exercise programs be developed based on CFS patientsí present abilities, not on what they
were able to do prior to having the disease. Range of motion exercises, such as lying hamstring stretch,
lateral bends, and lower back stretchers, can improve flexibility, decrease joint pain and enhance overall
functioning. Light resist-ance exercises, such as modified push-ups, step-ups, and flex-knee crunches,
can help to maintain and build strength.
Each exercise session should be comprised of very brief
periods of activity (30 seconds or less) followed by at least 1 minute of rest or until complete recovery
is achieved. Total periods of activity in a single session should not exceed 20 minutes.
principle to any exercise regimen is the necessity of allowing adequate time for recovery so that anaerobic
metabolites, such as lactic acid, are removed to facilitate further exercise. If excessive fatigue ensues,
decrease the number of exercises or their duration.
Determining whether a CFS patient has benefited
from exercise requires a different assessment approach than with individuals suf-
fering from other
illnesses. A return to pre-morbid fitness levels may not be pos-sible for CFS patients, but improvement
is possible. Practitioners, therefore, should have a clear picture of a patientís pre-exercise condition
(not pre-morbid condition) and compare it to post-exercise accomplishments, such as whether patients can
now independently perform tasks like vacuuming, doing the laundry, washing the dishes, etc., on a daily
basis, with shorter rest periods and without relapse, may be just as important as counting how many times
they can perform a particular exercise or assessing their cardiovascular condition.
McCully K et al. Impaired oxygen delivery to muscle in chronic fatigue
Science. 1999; 97: 603-608.
Snell CR et al. Comparison of maximal oxygen consumption and RNase-L enzyme
with chronic fatigue syndrome. JCFS. (In press.)
DeMeirlier K et al. A 37kDA 2-5A binding protein as a potential biochemical
chronic fatigue syndrome. Am J Med. 2000:108: 99-105.
Clapp L et al. Acute effects of thirty minutes of light-intensity, intermittent
on patients with chronic fatigue syndrome. Phys Therapy. 1999; 79(8):749-756.
VanNess J M et al. Exercise testing in patients with chronic fatigue syndrome
tool? Fed Amer Soc for Exp Bio J. 2000;14(4): LB41.