title: When does stress end? Evidence of a prolonged stress reaction in shiftworking truck drivers.
abstract: This study aimed to analyze individual cortisol levels in relation to work conditions, sleep, and health parameters among truck drivers working day shifts (n = 21) compared to those working irregular shifts (n = 21). A total of 42 male truck drivers (39.8 (+/-) 6.2 yrs) completed questionnaires about sociodemographics, job content, work environment, health, and lifestyle. Rest-activity profiles were measured using actigraphy, and cardiovascular blood parameters were collected. Salivary cortisol samples were obtained: (i) at waking time, (ii) 30?min after waking, and (iii) at bedtime, during both one workday and one day off from work. Irregular-shift workers, compared to day-shift workers, showed significantly higher waist-hip ratio, very-low-density lipoprotein (VLDL) cholesterol, tiredness after work, years working as a driver, truck vibration, and less job demand (p < .05). High cortisol levels in irregular-shift workers were correlated with certain stressors, such as short sleep duration and low job satisfaction, and to metabolic parameters, such as total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), VLDL, and triglycerides. Day-shift workers had higher cortisol levels collected 30?min after waking (p = .03) and a higher cortisol awakening response (CAR; p = .02) during workdays compared to off days. Irregular-shift workers had higher cortisol levels on their off days compared to day-shift workers (p = .03). In conclusion, for the day-shift workers, a higher cortisol response was observed on workdays compared to off days. Although no direct comparisons could be made between groups for work days, on off days the irregular-shift workers had higher cortisol levels compared to day-shift workers, suggesting a prolonged stress response in the irregular-shift group. In addition, cortisol levels were correlated with stressors and metabolic parameters. Future studies are warranted to investigate further stress responses in the context of irregular work hours.
authors.affiliation: School of Public Health, University of São Paulo, Brazil.
authors.forename: Melissa Ara Jo
authors.initials: MA
authors.lastname: Ulhôa
authors.forename: Elaine Cristina
authors.initials: EC
authors.lastname: Marqueze
authors.forename: Thomas
authors.initials: T
authors.lastname: Kantermann
authors.forename: Debra
authors.initials: D
authors.lastname: Skene
authors.forename: Claudia
authors.initials: C
authors.lastname: Moreno
mesh_terms: D000328:Adult; D001938:Brazil; D002940:Circadian Rhythm / Q000502:physiology*; D003430:Cross-Sectional Studies; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D018986:Motor Vehicles; D012463:Saliva / Q000378:metabolism; D013312:Stress, Physiological; D011795:Surveys and Questionnaires; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D006854:Hydrocortisone