Effects of caffeine consumption on intraocular pressure during low‐intensity endurance exercise: A placebo‐controlled, double‐blind, balanced crossover study. Vera Vílchez, Jesús Redondo Cabrera, Beatriz Bardón, Anabel Pérez Castilla, Alejandro García Ramos, Amador Jiménez Rodríguez, Raimundo caffeine glaucoma management glaucoma prevention ocular hypertension physical exercise rebound tonometry Abstract Importance: Intraocular pressure (IOP) is sensitive to caffeine intake and physical exercise. However, the combined effect of caffeine intake and physical exercise on IOP levels remains unknown. Background: We aimed to assess the effects of caffeine consumption before exercise on the IOP behaviour during low-intensity endurance exercise. Design: A placebo-controlled, double-blind, balanced crossover study at the University of Granada. Participants: Eighteen physically active young adults (age = 23.3 ± 2.4 years) participated in this study. Methods: Participants performed 30 minutes of cycling at 10% of maximal power production after 30 minutes of ingesting a capsule of caffeine (~4 mg/kg) and placebo in two different days and following a double-blind procedure. Main Outcome Measure: IOP was measured at baseline (before caffeine/placebo ingestion), after 5 minutes of warm-up, during cycling (6, 12, 18, 24 and 30 minutes) and recovery (5 and 10 minutes) by rebound tonometry. Results: There was a significant effect of caffeine consumption (P < .001, η2 = 0.50), showing that the ingestion of caffeine before exercise counteracted the IOP-lowering response to low-intensity endurance exercise. Greater IOP values at 12, 18, 24 and 30 minutes (corrected P-values<.05, ds = 0.90-1.08) of cycling were observed for the caffeine in comparison to the placebo condition. Conclusions and Relevance: The ingestion of caffeine (~4 mg/kg) 30 minutes before performing low-intensity endurance exercise counteracts the IOP-lowering effect of low-intensity exercise. These results highlight that the ingestion of a considerable amount of caffeine before exercise should be discouraged for individuals who would benefit from the IOP reduction associated with low-intensity exercise (ie, glaucoma patients or those at risk). 2025-01-13T11:39:22Z 2025-01-13T11:39:22Z 2020 journal article Clinical & Experimental Ophthalmology, 48(5): 602-609 https://hdl.handle.net/10481/98965 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Wiley