Effect of Ramadan Fasting on Visual and Auditory Reaction Time in Malaysian Medical Students Studying in India: A Prospective Observational Study

Introduction: Ramadan fasting, a significant religious practice, is associated with physiological and circadian alterations that may affect neurocognitive function, particularly reaction time, an objective marker of sensory-motor processing speed and alertness. Reaction time is especially relevant in medical students, who require sustained mental alertness and efficiency. Despite its importance, there is limited and inconsistent evidence on how Ramadan fasting affects reaction time in healthy Southeast Asian medical students. Aim: To assess the impact of Ramadan fasting on visual and auditory reaction times among healthy Malaysian medical students studying in India. Materials and Methods: This prospective observational study was conducted in the Department of Physiology at USMKLE International Medical Programme, Jawaharlal Nehru Medical College (JNMC) Campus, Belagavi, Karnataka, India, from February 2025 to March 2025. A total of 104 apparently healthy Malaysian medical students aged 18-25 years who were observing Ramadan fasting were included. Visual (green and red light) and auditory (tone and click) reaction times were measured using a standardised reaction time apparatus one week before Ramadan and during the fourth week of fasting to assess cumulative physiological and circadian effects of sustained fasting on reaction time. Data were analysed using the Wilcoxon signed-rank test and Mann-Whitney U test via Statistical Packages of Social Sciences (SPSS) version 23.0, with p<0.05 considered statistically significant. Results: The study included 40 males and 64 females with mean age 21.47±1.66 years. In male participants, both visual and auditory reaction times were significantly prolonged during the fasting period compared to the prefasting phase (p<0.001 for all parameters). Similarly, female participants also demonstrated a statistically highly significant increase in both visual and auditory reaction times during fasting compared to prefasting values (p<0.001 for all parameters). However, no significant gender differences in visual or auditory reaction times were observed during the fasting period. Conclusion: Ramadan fasting is associated with a significant delay in visual and auditory reaction times in both genders, indicating transient cognitive slowing in healthy young adults. These findings highlight the neurocognitive implications of Ramadan fasting, particularly in tasks requiring rapid visual and auditory responses.