Dados do Trabalho

Título

Fatigue of Shift Workers: Assessment by Postural Control

Introdução

Fatigue can be assessed through postural balance, which is considered effective and robust to assess awake time and, consequently, fatigue (Pham et al., 2014). Postural sway can be used to estimate the fatigue level of workers before their workdays and has a positive correlation with sleepiness levels inferred through the Karolinska Sleepiness Scale (Narciso et al., 2016).

Objetivo

The aim of this work is to evaluate whether postural sway at the beginning of the shift projects fatigue in the middle and at the end of the shift differently, according to the start time of the shift.

Métodos

In this study, we used the prototype device called Sonômetro, which has an internal mechanism for measuring postural sway and is wearable, attached to the body, close to the height of the center of mass. Each assessment includes records of the start and end time of sleep, travel to the workplace, start and end of the day to be exercised in the work. Control is done through the Sonômetro Light app, connected via bluetooth. Thirty-four workers on a fast counterclockwise shift work (4x1) were evaluated and the instant data (beginning of shift), projection for mid-shift and projection for the end of the shift between the 4 shifts: night, afternoon, morning and dawn were compared. The gamma distribution with the identity function was considered for data analysis through the method of generalized linear models, through the computer program SPSS 20.0.

Resultados

The scores obtained for the night shift were 12.05, 12.99 and 14.44 for the beginning, middle and end. In the evaluation of the afternoon shift, the scores were 9.6, 10.03 and 10.38. The morning shift scores were 9.85, 10.6 and 11.17. Finally, the scores for the morning shift were 14.71, 22.15 and 27.6. The result of the pairwise comparisons indicated that there are differences in postural sway, being greater at the beginning of the morning shift, only in relation to the afternoon shift. In the middle of the shift, a difference was found between the morning shift and all others, as well as at the end of the shift.

Conclusões

Our findings allow us to infer that the homeostatic process in shift workers has a greater impact when the circadian process is neglected due to the working day. Workers with postural sway similar to the beginning of the shift have a greater increase in sway when they work at dawn, indicating accumulation of fatigue accentuated by the absence of night sleep.

Palavras -chave

Shiftwork
Fatigue
Sonômetro
Postural control
work safety