RESUMO
It is well established that adrenal hormone cortisol has long been used in human psychobiological studies as a biological marker of circadian rhythm, stress, and anxiety. There is little information, however, about the anxiety. There is little information, however, about the interrelationships of night work, plasma cortisol levels in females' nurses of the developing countries. The aim of the present study was to compare circadian cortisol profile between two groups of nurses with shift and permanent work in a hospital affiliated to Shiraz University of Medical Sciences, Iran, between January 2006 to September 2008. In this experimental study, we examined the reproducibility of plasma cortisol levels during one month period in 34 shift work nurses and 10 permanent day shift works. We evaluated potential associations between night work and hormone levels, using current and shift work information for the health care shift workers. The results clearly revealed that shift work significantly increased nighttime cortisol levels [34.93 micro g/dl] during night shift and decreased the peak levels of cortisol in the morning [39.03 microg/dl]. During the work shift the plasma cortisol presented a decreased concentration in the morning and increasing levels [44.93 micro g/dl] by the end of the evening. In contrast, the permanent day work nurses, who had never worked at night shits, showed a lowest secretion of cortisol during the first half of night time sleep [10.02 micro g/dl], and a peak value of the cortisol after awakening at 07:00h [59.75 micro g/ml]. We also observed a significant association between night work and increased levels of cortisol over the remaining of the day. It can be concluded that nurses with night shift work have an abnormal cortisol secretion profile. Shift work nurses on rotating night shifts seem to experience changes in hormones levels that may be associated with increased of circadian disorders risk observed among night -shift workers