DISSOCIATION OF BODY-TEMPERATURE AND MELATONIN SECRETION CIRCADIAN-RHYTHMS IN PATIENTS WITH CHRONIC FATIGUE SYNDROME

Many patients with chronic fatigue syndrome (CFS) display features of hypothalamic dysfunction, We have investigated aspects of circadian rh ythmicity, an important hypothalamic function, in 20 CFS patients and in 17 age- and sex-matched healthy control subjects, There were no dif ferences between the two groups in the amplitude, mesor (mean value) o r timing of the peak (acrophase) of the circardian rhythm of core temp erature, or in the timing of the onset of melatonin secretion. However , the CFS patients showed no significant correlation between the timin g of the temperature acrophase and the melatonin onset (P<0.5), wherea s the normal significant correlation was observed in the controls (P<0 .05). :Dissociation of circadian rhythms could be due to the sleep dep rivation and social disruption, and/or the reduction in physical activ ity which typically accompany CFS. By analogy with jet-lag and shift-w orking, circadian dysrhythmia could be an important factor in initiati ng and perpetuating the cardinal symptoms of CFS, notably tiredness, i mpaired concentration and intellectual impairment.