title: Quantification of cumulated physical fatigue at the workplace.
abstract: Quantification of physical fatigue remains a challenge. We hypothesized that its effects on central autonomic nervous system activity could be explored for such a quantification. To test this relationship, we prospectively measured central autonomic nervous activity through nocturnal heart rate variability (HRV) in six French garbage collectors, aged 32.1+/-4.3 years, twice a week during 3 consecutive weeks of work, and during the following week of rest. Eight healthy sedentary males formed a control group. HRV indices were calculated by applying standard temporal domain and wavelet transform analyses to standard ECG recordings. During the 3 consecutive weeks of work, there was a significantly progressive decrease in HRV indices, particularly pNN50 (-34.2%, P<0.05), as well as the high (-33.3%, P<0.05) and low (-22.2%, P<0.01) frequency components of wavelet transform, while there was an increase, although non-significant, of the ratio of low to high frequencies (9.1%). During the resting period, there was a significant recovery of HRV indices, notably of its high (50.0%, P<0.05) and low (28.6%, P<0.05) frequency components. No such changes occurred in the control group. A central signature of cumulated physical fatigue can thus be detected and quantified through nocturnal autonomic nervous system activity. Its characteristics are those of a progressive parasympathetic withdrawal.
authors.affiliation: Exploration Fonctionnelle CardioRespiratoire, Laboratoire de Physiologie, GIP E2S, Groupe PPEH, Hôpital Nord Niveau 6, 42055 Saint-Etienne Cedex 2, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Pichot
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Bourin
authors.forename: Frédéric
authors.initials: F
authors.lastname: Roche
authors.forename: Martin
authors.initials: M
authors.lastname: Garet
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Gaspoz
authors.forename: David
authors.initials: D
authors.lastname: Duverney
authors.forename: Anestis
authors.initials: A
authors.lastname: Antoniadis
authors.forename: Jean-René
authors.initials: JR
authors.lastname: Lacour
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Barthélémy
mesh_terms: D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology*; D016022:Case-Control Studies; D002940:Circadian Rhythm; D004562:Electrocardiography; D005221:Fatigue / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D012146:Rest; D014937:Work; D016526:Workload