PHYSICAL-ACTIVITY IN CHRONIC-FATIGUE-SYNDROME - ASSESSMENT AND ITS ROLE IN FATIGUE

This paper describes the assessment of physical activity in chronic fa tigue syndrome (CFS) and investigated the following questions: Do pati ents with CFS have low levels of physical activity: is there a relatio nship between actual level of physical activity and fatigue; can self- report measures adequately assess actual level of physical activity; w hat is the role of cognitions with respect to physical activity; and a re results with respect to physical activity specific to CFS? Three di fferent types of activity measures were used: self-report questionnair es, a 12-day self-observation list, and a motion-sensing device (Actom eter) which was used as a reference for actual activity level. Fifty-o ne patients with CFS, 50 fatigued patients with multiple sclerosis (MS ), and 53 healthy subjects participated in this study. Although none o f the self-report questionnaires showed high correlations with the Act ometer, questionnaires that require simple ratings of specified activi ties were related to the Actometer and can be used as acceptable subst itutes, in contrast to instruments that require general subjective int erpretations of activity that had low or non-significant correlations with the Actometer. Actometer results showed that CFS patients and MS patients had similar activity levels and both groups were significantl y less active than healthy subjects. Compared to MS patients, CFS pati ents were more likely to indicate that they had been less active than other persons they knew. Activities which patients expected to result in higher fatigue levels were less frequently performed. Patients with CFS had significantly higher scores on this measure than MS patients and healthy subjects. Low levels of physical activity were related to severe fatigue in CFS but not in MS. In conclusion, although CFS patie nts have similar low activity levels than MS patients, there are also important differences between both groups: in CFS cognitive factors ar e more prominently involved in producing the low activity levels than in MS and in CFS patients activity level is related to fatigue but not in MS. (C) 1997 Elsevier Science Ltd. All rights reserved.