Vanness JM, Stevens SR, Bateman L, Stiles TL, Snell CR
Pacific Fatigue Laboratory, University of the Pacific , Stockton, California.
J Womens Health (Larchmt). 2010 Jan 24
Objective: Postexertional malaise (PEM) is a defining characteristic
of chronic fatigue syndrome (CFS) that remains a source of some
controversy. The purpose of this study was to explore the effects of
an exercise challenge on CFS symptoms from a patient perspective.
Methods: This study included 25 female CFS patients and 23 age-matched
sedentary controls. All participants underwent a maximal
cardiopulmonary exercise test. Subjects completed a health and
well-being survey (SF-36) 7 days postexercise. Subjects also provided,
approximately 7 days after testing, written answers to open-ended
questions pertaining to physical and cognitive responses to the test
and length of recovery. SF-36 data were compared using multivariate
analyses. Written questionnaire responses were used to determine
recovery time as well as number and type of symptoms experienced.
Results: Written questionnaires revealed that within 24 hours of the
test, 85% of controls indicated full recovery, in contrast to 0 CFS
patients. The remaining 15% of controls recovered within 48 hours of
the test. In contrast, only 1 CFS patient recovered within 48 hours.
Symptoms reported after the exercise test included fatigue,
light-headedness, muscular/joint pain, cognitive dysfunction,
headache, nausea, physical weakness, trembling/instability, insomnia,
and sore throat/glands. A significant multivariate effect for the
SF-36 responses (p < 0.001) indicated lower functioning among the CFS
patients, which was most pronounced for items measuring physiological
Conclusions: The results of this study suggest that PEM is both a real
and an incapacitating condition for women with CFS and that their
responses to exercise are distinctively different from those of