International Journal of Medical Education. 2014;5:56-62 ISSN: 2042-6372 DOI: 10.5116/ijme.531a.f2c9 56 © 2014 Isabel Pérez-Olmos & Milcíades Ibáñez-Pinilla. This is an Open Access article distributed under the terms of the Creative Commons Attribution License which permits unrestricted use of work provided the original work is properly cited. http://creativecommons.org/licenses/by/3.0 Night shifts, sleep deprivation, and attention performance in medical students Isabel Pérez-Olmos, Milcíades Ibáñez-Pinilla Research Center of the School of Medicine and Health Sciences, Rosario University, Colombia Correspondence: Isabel Pérez-Olmos, Research Center of the School of Medicine and Health Sciences, Rosario University, Colombia Email: isabel.perez@urosario.edu.co Accepted: March 08, 2014 Abstract Objectives: To determine attention performance of medical students after sleep deprivation due to night shift work. Methods: Prospective cohort design. All seventh, eighth and ninth semester students were invited to participate (n= 209). The effectiveness and concentration indices (d2 Test for attention, dependent variable) from 180 students at 3 evaluations during the semester were compared. Eighth and ninth semester students underwent their second evaluation after a night shift. The independent variables were noctur- nal sleep measurements. Results: No differences in nocturnal sleep hours during the previous week (p=0.966), sleep deprivation (p=0.703) or effectiveness in the d2 Test (p=0.428) were found between the groups at the beginning of the semester. At the begin- ning and the end of the semester, the d2 Test results were not different between groups (p=0.410, p=0.394) respective- ly. The second evaluation showed greater sleep deprivation in students with night shift work (p<0.001). The sleep deprived students had lower concentration indices (p<0.001).The differences were associated with the magni- tude of sleep deprivation (p=0.008). Multivariate regression analysis showed that attention performance was explained by sleep deprivation due to night shift work, adjusting for age and gender. Students with sleep deprivation had worse concentration than those without. Conclusions: Sleep deprivation due to night shift work in medical students had a negative impact on their attention performance. Medical educators should address these potential negative learning and patient care consequences of sleep deprivation in medical students due to night shifts. Keywords: Sleep deprivation, nightshift work, attention performance, undergraduate medical students, Colombia Introduction Many authors have emphasized the importance of sleep for optimal cognitive and emotional performance, learning, memory consolidation, affective regulation, 1-4 attention, and concentration, 5 among other related aspects. 6-8 Moreo- ver, some studies indicate that hippocampal neurogenesis, especially in the dentate gyrus, involved in learning and memory processes, is considered to be sleep dependent. 9-11 Despite these evidences, some other authors have ques- tioned the role of sleep in memory consolidation. 12 Scientific literature has shown that occupational activi- ties with shifts that alter circadian sleep/wakefulness cycles lead to sleep deprivation (SD). In humans, sleep depriva- tion is associated with diurnal somnolence; 13 attention, memory, and learning process deficits; and, in general, alterations in cognitive performance. 14,15 It has also been shown that when SD is cumulative, there can be negative consequences for general health and productivity, as well as an increased risk of accidents. 16 Some authors point out the need to take into account individual differences in the effects of SD, since there are indications of systematic features of individual vulnerability which warrant better definition and more research. 17 Research animal models have been created to facilitate the understanding of the neurobiological mechanisms underlying sleep/wakefulness cycles, altered sleep patterns, and cognitive deficits resulting from SD and fragmented sleep, which cannot be explored in human subjects. 15 Notwithstanding these considerations, SD is inherent to medical education and clinical practice, even though health care is the main objective of the profession. Paradoxically, the negative consequences of SD in medical students have not been considered in some countries. It is thus important to determine the implications of sleep deprivation resulting from night-time shifts on daytime cognitive performance, learning, patient care, and in general the quality of life of health professionals, particularly medical students during their professional education. This is especially so, given the high academic demands and optimal patient care expected