title: Social Jetlag Among Night Workers is Negatively Associated with the Frequency of Moderate or Vigorous Physical Activity and with Energy Expenditure Related to Physical Activity.
abstract: This cross-sectional study analyzed the association between physical activity (PA) and social jetlag (SJL) among shift workers. We evaluated 423 employees, aged between 18 and 60 years, who worked in a poultry-processing company in Brazil. Physical activity levels (PAL) were determined by the short form of the International Physical Activity Questionnaire (IPAQ-SF). SJL was calculated as the absolute difference between the time of mid-sleep on work and free days. The percentage of workers insufficiently active was high on all shifts, with no significant differences between the 3 shifts. The amount of time spent in sedentary behavior on workdays did not differ between shifts. Among night-shift workers, negative associations were observed between SJL and 1) the duration and weekly energy expenditure while walking; 2) the frequency of moderate and vigorous PA; and 3) the total energy expenditure related to PA. Even though PAL did not differ among workers on different shifts, we found a high prevalence of subjects who were insufficiently active or too sedentary among all groups. Also, SJL was negatively associated with PA in night-shift workers. These results suggest that PA should be encouraged among shift workers and that SJL may be an important factor in reducing PA in this cohort.
authors.affiliation: Post-Graduate Program in Health Sciences, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Mariana Silva
authors.initials: MS
authors.lastname: Alves
authors.affiliation: Post-Graduate Program in Health Sciences, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Raphael Zardini
authors.initials: RZ
authors.lastname: Andrade
authors.affiliation: Post-Graduate Program in Health Sciences, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Graciele Cristina
authors.initials: GC
authors.lastname: Silva
authors.affiliation: Post-Graduate Program in Health Sciences, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Maria Carliana
authors.initials: MC
authors.lastname: Mota
authors.affiliation: Post-Graduate Program in Health Sciences, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Sabrina Gonçalves
authors.initials: SG
authors.lastname: Resende
authors.affiliation: Post-Graduate Program in Health Sciences, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Kely Raspante
authors.initials: KR
authors.lastname: Teixeira
authors.affiliation: Graduate in Nutrition, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Bruna Fernandes
authors.initials: BF
authors.lastname: Gonçalves
authors.affiliation: Post-Graduate Program in Health Sciences, Faculty of Medicine, Federal University of Uberlândia, Uberlândia, Brazil.
authors.forename: Cibele Aparecida
authors.initials: CA
authors.lastname: Crispim
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D020179:Jet Lag Syndrome / Q000503:physiopathology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D012890:Sleep / Q000502:physiology*; D011795:Surveys and Questionnaires; D013997:Time Factors; D016138:Walking; D014940:Work Schedule Tolerance / Q000502:physiology*
keywords: energy expenditure; physical activity level; shift work; sleep; social jetlag