Efeitos de 8 semanas de exercício físico de curta duração em parâmetros subjetivos e objetivos do sono de trabalhadores por turnos

Abstract

The practice of physical exercises is an important behavioral factor for health, however approximately 25% of adults remain sedentary. Adults organize their lives around working hours. Shift work impairs sleep and eating, and the chronic sleep restriction characteristic of shift workers is associated with increased body mass. In addition, lack of time is one of the main barriers to regular physical exercise in shift workers. OBJECTIVES: To evaluate the effects of eight weeks of physical exercise for 30 minutes and 3 times a week, on sleep, on sleep complaints and on body composition, in rotating shift workers. METHODS: Convenience sample, with male and female volunteers between 18 and 50 years of age, mining truck operators. Bioimpedance, questionnaires and sleep assessment by actigraphy (15 days) were performed. Participants were allocated to one of three groups (control, exercise on an oscillating platform or exercise with a rubber band). After 8 weeks of intervention, reassessments were performed. The study was approved by the Research Ethics Committee of the Federal University of Minas Gerais (CAAE-nº:97394818.6.0000.5149). Descriptive data analysis and frequency analysis were performed to characterize the sample. The generalized linear model (GEE) was applied to describe the effect of group and time on sleep and body composition variables. Group and time were considered as a fixed effect, controlled by age and time working on the scale. A significance level of p<0.05 was adopted. RESULTS: The workers evaluated had better sleep time and body composition than expected in the general population and shift workers, as well as a lower prevalence of sleep complaints. A significant effect of the interaction between group and treatment (Wald Chi-Square 7.59, degrees of freedom:3, p=0.05) was observed, with a reduction of approximately 32 minutes in the general average of the total sleep time of the control group, while the groups intervention maintained total sleep time. A significant reduction in the need for rest was observed in all groups (Wald Chi-Square 4.1, degrees of freedom: 1, p=0.04) in the post moment in relation to the pre moment. All groups had a lower prevalence of sleep complaints in the postpartum period, although not significant. No improvements in body composition were observed after the intervention. Adherence to training sessions in both groups was greater than 95%. CONCLUSION: The group of workers evaluated presented sleep parameters, sleep complaints and body composition better than expected in shift workers and thus presented a ceiling effect for the variables evaluated at baseline. The intervention group benefited from maintaining total sleep time, which was reduced in the control group. The interventions proved to be viable and with high adherence of workers, indicating that it is possible for workers in fast rotating shifts to practice physical exercise on a regular basis. Considering the ceiling effect, in order to obtain positive effects on workers' body composition and sleep, future interventions need to be directed at overweight workers or with sleep complaints or low TTS and maintained for periods longer than 8 weeks.