Heart Rate Orcadian Rhythm as a Biological Marker of Desynchronization in Major Depression: A Methodological and Preliminary Report

Abstract

Heart rate (HR) was continuously monitored during successive 24-hr periods in 19 healthy subjects and 26 major depressed patients (DSM III-R). Recordings were performed after a 2-week wash-out period and the morningness or eveningness typology of each subject was determined. The chronobiological parameters and rhythm percentage (RP) were calculated by the single cosinor method from the smoothed HR curves of each subject. In normal subjects, HR follows a circadian rhythm (RP greater than 65%) with the lowest values at night. Morning type subjects have an earlier peak time (13:30) than evening type subjects (17:30). Major depressive patients were split into two groups; in the first one HR circadian rhythm was still present (RP greater than 63%) with a decrease in amplitude (24%) while in the second group, no circadian rhythm of HR could be detected (RP less than 25%, decrease in amplitude greater than 70%). In the group of patients with a persisting HR circadian rhythm, no veritable phase advance was observed. Our results suggest that circadian HR rhythm, which can be easily studied with non-invasive methods, might represent a chronobiological marker of some depressions. Given the lag that exists between the rhythms of morning type and evening type subjects, our study also stresses the importance of taking into account this behavioural trait in chronobiological studies.

Evening types are prone to depression

“…However, the large sample size meant that such measurements would be challenging. Second, an apparent difference has been reported between morning types and evening types in the peak time of heart rate (13:30 vs. 17:30 h) during continuous monitoring (Taillard et al, 1990), indicating a circadian rhythm, which may also have influenced our findings on resting heart rate. This is, however, unlikely, since the health examinations during which resting heart rates were recorded in our study took place between 10:55 and 20:10 h, the attendance time being 14:50 h on average, and there was no marked difference in the assessment time by chronotype.…”

Variability of behavioral chronotypes of 16 mammalian species under controlled conditions

“…The behavioral typology of morningness and eveningness in humans is consistent with the timing of the rhythms of body temperature [4,5], heart rate [6,7], melatonin secretion [8,9], and other physiological variables. Perhaps because significant correlations have been found between morningness-eveningness and several psychological traits [10][11][12][13][14], the classification of chronotypes has attracted great attention from social scientists.…”

Autonomic neuropathy in hemodialysis patients: questionnaires versus clinical tests

“…Another possible explanation is that we did not use aluminium hydroxide as a phosphate binder in any of our patients and aluminium neuropathy might have been responsible for a higher frequency of AN found in some earlier studies [8]. It is, however, of note that even efficient dialysis treatment does not provide a definite cure for AN, the pathogenesis of which is multifactorial [9,10]. Significant discrepancies between objective and subjective AN symptoms found in our study may also reflect the presence of chronic illness and long-term suffering as a result of chronic hemodialysis treatment.…”