Background and aims Some social systems if necessary 'are obliged to recruit their personnel in rotation shifts.on the other hand working rotatedly disrupts persons biological rhythms and this may cause some disorders in their body physiology and make tobe affected to physical 'psychological'and social disorders.so'this research is accomplished to determin the level of serum cortisol and aldest...

Introduction: In modern societies, shift work is an essential component of daily life. Since the beginning of research in shift work, researchers have been engaged in the identification of factors predicting adjustment and adaptation to shift work. The concept of adaptation and tolerance refers mainly to the biological response in terms of circadian rhythms and performance efficiency as well as...