Arrhythmias and increased neuro-endocrine stress response during physicians' night shifts: a randomized cross-over trial.
OBJECTIVE
To evaluate the effects of a 24 h (h) physicians on-call duty (OCD) ('night shift') on 24 h electrocardiogram (ECG), heart rate variability, blood pressure (BP), and various biochemical serum and urine 'stress markers' compared with a 'regular' day at work.


RESULTS
The study was designed as a prospective randomized cross-over trial with each physician completing a 24 h (h) OCD and a 24 h control period including a regular 8 h non-OCD. Thirty healthy physicians with a median age of 33.5 years (range 29.0-45.0) were analysed. Twenty-four hours ECG and BP monitoring were performed and participants were instructed to fill out an event diary and perform a 24 h urine collection. Furthermore, blood was drawn before and after OCD and control day. Twenty-four hours ECG showed a higher rate of ventricular premature beats (VPB) during early morning hours (VPB 0-6 h, 0.5 vs. 0.0, P = 0.047) and increased low-frequency normalized units (29.3 vs. 25.5, P = 0.050) during night shift when compared with respective control night at home. During OCD, BP monitoring revealed a greater diastolic BP throughout 24 h (83.5 vs. 80.2 mmHg, P = 0.025) as well as during night-time (75.4 vs. 73.0, P = 0.028) associated with a higher rate of systolic BP more than 125 mmHg during sleep time. Tumour necrosis factor alpha concentrations increased significantly during night shift (0.76 vs. 0.05 pg/mL, P = 0.045). Urinary noradrenaline excretion was greater during OCD when compared with control day (46.0 vs. 36.0 microg/24 h, P = 0.007).


CONCLUSIONS
Our results highlight the association of OCD with an increased risk profile for cardiovascular disease. In addition to the acute effects observed, frequent night-calls over a longer period possibly elicit sustained alterations in cardiovascular homeostasis.
Rauchenzauner
Markus
M
Department of Pediatrics, Medical University Innsbruck, A-6020 Innsbruck, Austria.
Ernst
Florian
F
Hintringer
Florian
F
Ulmer
Hanno
H
Ebenbichler
Christoph F
CF
Kasseroler
Marie-Therese
MT
Joannidis
Michael
M
D000328:Adult; D001145:Arrhythmias, Cardiac / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D015415:Biomarkers / Q000378:metabolism*; D001794:Blood Pressure / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D018592:Cross-Over Studies; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009784:Occupational Diseases / Q000097:blood / Q000209:etiology* / Q000503:physiopathology; D010561:Personnel Staffing and Scheduling; D010820:Physicians; D013315:Stress, Psychological / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D014940:Work Schedule Tolerance / Q000502:physiology*
D015415:Biomarkers