title: Effect of an aerobic exercise intervention on cardiac autonomic regulation: A worksite RCT among cleaners.
abstract: The aim of this randomized controlled trial (RCT) was to determine whether aerobic exercise during work hours affects cardiac autonomic regulation in cleaners characterized by high levels of occupational physical activity and poor cardiorespiratory fitness.
  
  
  
  Eligible cleaners (n=116) were randomized to an aerobic exercise group (n=59) or a reference group (n=57) with lectures. The intervention group received two 30-min sessions per week of supervised aerobic exercise over 4months. Diurnal measurements of heart rate variability (HRV) and physical activity (accelerometry) were obtained at baseline and at 4-month follow-up. Time and frequency domain indices of HRV were derived during work, leisure time and sleep to evaluate cardiac autonomic regulation. Linear mixed models were used to determine the effect of the intervention on HRV indices, with adjustment for age, gender and daily use of antihypertensive and/or heart medication.
  
  
  
  Compared with the reference group, the exercise group increased all HRV indices apart from a reduction in LF/HF ratio from baseline to follow-up both during work (p<0.05) and leisure (p<0.05). In contrast, during sleep, the HRV indices tended to decrease in the exercise group compared with the reference group from baseline to follow-up, being significant for the HF spectral component (p=0.03).
  
  
  
  Among cleaners, a worksite aerobic exercise intervention improved cardiac autonomic regulation during work and leisure, but not during sleep. The health effect of this contrasting change in autonomic regulation needs further investigation.
authors.affiliation: Department of Occupational and Public Health Sciences, Centre for Musculoskeletal Research, University of Gävle, Kungsbäcksvägen 47, 801 76, Gävle, Sweden. Electronic address: David.Hallman@hig.se.
authors.forename: David M
authors.initials: DM
authors.lastname: Hallman
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark; Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
authors.forename: Andreas
authors.initials: A
authors.lastname: Holtermann
authors.affiliation: Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
authors.forename: Karen
authors.initials: K
authors.lastname: Søgaard
authors.affiliation: Department of Nutrition, Exercise and Sports, Copenhagen Centre for Team Sport and Health, University of Copenhagen, Nørre Allé 51, 2200 Copenhagen N, Denmark; Sport and Health Sciences, Faculty of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Krustrup
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Kristiansen
authors.affiliation: National Research Centre for the Working Environment, Lersø Parkallé 105, 2100 Copenhagen Ø, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Korshøj
mesh_terms: D061725:Accelerometry; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption; D012680:Sensitivity and Specificity; D012890:Sleep / Q000502:physiology; D017132:Workplace
keywords: Autonomic; Cardiovascular; Objective measurements; Occupational health; Parasympathetic; Physical activity; Randomized controlled trial