Effect of skipping breakfast on autonomic nervous activity during a face recognition test in healthy young men

BACKGROUND: This study aimed to investigate the influence of skipping breakfast on the autonomic nervous system during the performance of a mental load. METHODS: In 40 male university students (mean age, 20.9 years) who either ate breakfast every day or did not eat at breakfast every day, blood glucose and autonomic nerve activity measured by electrocardiography were monitored during a mental load (face recognition test), the day of eating as a meal, the day of not eating breakfast and the day of drinking 100% glucose juice, and cross-over evaluations were performed. RESULTS: The levels of blood glucose on the day were significantly lower on the day breakfast was not eaten than eaten or drank (P<0.05). In contrast, sympathetic nervous activity was significantly higher on the day breakfast was not eaten than eaten or drank at rest (P<0.05). Changes in sympathetic nervous activity before and after answering the face recognition test were significantly lower on the day of breakfast was not eaten than the day of glucose was drunk (P<0.05). Also, the changes in sympathetic nerve activity both changes answering the face recognition test and at rest were moderate on days when breakfast was taken as a meal. No differences were observed due to breakfast habits. CONCLUSIONS: This study suggested that both the day of skipping breakfast and the day of drinking 100% glucose juice may cause mental stress at rest (before the performance of face recognition tests) already because of the high symnomic nervous activity during a face recognition test in healthy young men. Gazz Med Ital - Arch Sci Med 2024;183:137-45.