title: Sleep habits, alertness, cortisol levels, and cardiac autonomic activity in short-distance bus drivers: differences between morning and afternoon shifts.
abstract: OBJECTIVE
  To evaluate sleep, alertness, salivary cortisol levels, and autonomic activity in the afternoon and morning shifts of a sample of short-distance bus drivers.
  
  
  METHODS
  A sample of 47 bus drivers was evaluated. Data regarding subjects and working characteristics, alertness (psychomotor vigilance task), sleep habits (Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, Actigraphy), endocrine stress response (salivary cortisol), and autonomic activity (heart-rate variability) were collected.
  
  
  RESULTS
  Sleep restriction was highly prevalent. Drivers in the morning shift slept 1 hour less than those in the afternoon shift, showed lower reaction time performance, a flattening of cortisol morning-evening difference, and higher overweight prevalence.
  
  
  CONCLUSIONS
  The differences found between morning and afternoon shifts point out to the need of the implementation of educational strategies to compensate the sleep loss associated with an early work schedule.
authors.affiliation: Departamento de Fisiología, Universidad Austral, Buenos Aires, Argentina.
authors.forename: Joaquín J
authors.initials: JJ
authors.lastname: Diez
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Vigo
authors.forename: Santiago Pérez
authors.initials: SP
authors.lastname: Lloret
authors.forename: Stephanie
authors.initials: S
authors.lastname: Rigters
authors.forename: Noelia
authors.initials: N
authors.lastname: Role
authors.forename: Daniel P
authors.initials: DP
authors.lastname: Cardinali
authors.forename: Daniel Pérez
authors.initials: DP
authors.lastname: Chada
mesh_terms: D000328:Adult; D001118:Argentina / Q000453:epidemiology; D001334:Automobile Driving; D001341:Autonomic Nervous System / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D006321:Heart / Q000294:innervation / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis / Q000502:physiology*; D008297:Male; D050177:Overweight / Q000453:epidemiology / Q000503:physiopathology; D015995:Prevalence; D011930:Reaction Time / Q000502:physiology; D012463:Saliva / Q000737:chemistry; D012890:Sleep / Q000502:physiology*
chemical_list: D006854:Hydrocortisone