Related Experiment Videos
The circadian melatonin and cortisol secretion pattern in permanent night shift workers
1Division of Clinical Endocrinology and Diabetes Mellitus, University of Vienna, Austria.
The American Journal of Physiology
|July 1, 1993
Summary
Permanent night shift workers often maintain their internal body clock orientation. High work satisfaction may be linked to factors beyond circadian system re-alignment, suggesting other mechanisms for shift work tolerance.
Area of Science:
- Chronobiology
- Occupational Health
Background:
- Conflicting reports exist on how permanent night shift work affects the circadian system.
- Understanding circadian rhythm adjustments is crucial for shift work tolerance.
Purpose of the Study:
- To investigate the impact of permanent night shift work on the circadian secretion patterns of melatonin and cortisol.
- To explore the relationship between work satisfaction and circadian system orientation in night shift workers.
Main Methods:
- Assessed circadian melatonin (MT) and cortisol secretion patterns in nine permanent night shift workers and seven controls.
- Collected blood samples hourly over 28 hours in a research facility.
- Analyzed hormonal profiles for phase, amplitude, and secretion patterns.
Main Results:
- Most permanent night shift workers maintained normal phase relationships between melatonin and cortisol.
- A trend towards elevated melatonin amplitude and secretion was observed in shift workers.
- One individual showed inverse hormone rhythms but also an inverse personal day-night rhythm.
Conclusions:
- Permanent night shift workers with high job satisfaction generally retain diurnal orientation of their endogenous clock.
- Circadian system reorientation may not be the primary factor for high tolerance to shift work.
- Other individual or environmental factors likely play a significant role in shift work adaptation.