2011 Volume 22 Issue 3 Pages 117-124
The objective of this research is to reveal the influence of chronic psychosomatic stress such as night work by measuring the diurnal variation of salivary amylase activity (SAA). Fourteen medical providers who engaged in 24-hour uninterrupted service consisting of daytime and night-time duties in the emergency department were enrolled as the subjects. Diurnal variations over 2 days including a workday and a holiday were measured three times in a month for each subject. Salivary amylase activities were measured 7 times over these 2 days. Diurnal variations showed SAA increased from the morning to before evening meal and decreased until the next morning, which can be described as a convex curve in both workday and holiday. Dynamic programming method was used to compare a similarity of two curves. The similarity between workday and holiday curves was 0.72, suggesting that phase and shape between the two mean curves was changed. The similarities of medical doctor and paramedical staff were 0.94 of workdays and 0.93 of holiday, showing high similarity without being dependent on the day. The similarity between each individual and mean diurnal variation was 0.34±0.57 in a workday and 0.43±0.50 on a holiday, which suggested that the diurnal variations of SAA showed highly individual. Our results revealed that the hard nocturnal work is possibly reflected in the diurnal variations of SAA not depending on a difference in occupation.