Introduction: University exam periods are marked by increased workload and pressure to perform, leading to changes in lifestyle habits. These changes can strongly affect the physiological and psychological state of students. Objective: This study examines the influence of exam periods on the state of vigilance of students at the UFR Biosciences of the Félix HOUPHOUËT-BOIGNY University of Abidjan (Côte d’Ivoire). Methodology: A questionnaire survey was conducted among 100 students, including 50 during exam periods and 50 outside exam periods. Results: The results reveal a significant reduction in sleep duration during exams (5.54 ± 1.33 hours compared to 8.50 ± 1.64 hours during normal periods) and an increase in revision time (4.38 ± 1.85 hours versus 2 ± 0.88 hours). The alertness index decreased significantly during exams (0.95 ± 0.20 versus 1.67 ± 0.26). However, neither the number of examinations per day, nor the timing of revisions, nor their duration have a significant impact on vigilance. Thesis results suggest that exam periods negatively affect students ' alertness, mainly due to changes in sleep and study habits. Conclusion: This study highlights the importance of a balance between revision and rest to maintain optimal alertness during exams.