Introduction: Carbohydrate and caffeine mouth rinses are commonly used to enhance athletic performance. This study aims to examine the combined effect of time of day and mouth rinsing with a carbohydrate and caffeine solution on time to exhaustion, levels of the inflammatory marker C-reactive protein (CRP), and muscle strength in female athletes. Method: A total of 24 non-menopausal female athletes were recruited for the study and randomly assigned to either an experimental (N=12) and control (N=12) group. Participants underwent the Bruce treadmill test twice, once in the morning and once in the evening. In a single-blind design, the experimental group received 25 cc of 6% glucose + 1.2% caffeine solution, while the control group received 25 cc of distilled water solution in the interval of 30 minutes before the start of the test, every 15 minutes, they reeled in the mouth for 10 seconds and poured it out.The variables measured included time to exhaustion, CRP levels, and muscle strength, both in the morning and evening. Data were analyzed using repeated measures ANOVA. Results: No significant differences were found between the experimental and control groups regarding time to exhaustion or chest press performance, regardless of the time of day (P ≥ 0.05). However, time of day had a significant effect on CRP levels (p = 0.006). Additionally, there was a significant interaction between time of day and group (p = 0.03), and the group effect on CRP levels was also significant (p = 0.05). Notably, CRP levels were significantly higher in the evening compared to the morning and baseline levels (p = 0.01). Conclusion: The findings suggest that a carbohydrate and caffeine mouth rinse can significantly influence the inflammatory response, with a more pronounced effect observed in the evening. This strategy may be beneficial for improving the health and performance of female athletes.
Khorshidian N, Zar A, Sadeghipour H. The Interaction Effect of Time of Day and Mouth Rinsing with Carbohydrate and Caffeine Solution on Time to Exhaustion, Inflammatory Marker CRP, and Muscle Strength in Female Athletes. armaghanj 2025; 30 (2) URL: http://armaghanj.yums.ac.ir/article-1-3706-en.html