Intraocular Pressure Increases in Parallel with Systemic Blood Pressure during Isometric Exercise

Abstract

PURPOSE: Normal-tension glaucoma has been found to be related to transient increases in intraocular pressure (IOP). Isometric exercise induces a pressor response with a characteristic increase in blood pressure. The purpose of the present study was to investigate how transient changes in systemic blood pressure, induced by isometric exercise, affect IOP. METHODS: Nine healthy volunteers participated in the study. Systemic blood pressure, heart rate (ECG) and IOP (electronic continuous-indentation tonometer) were recorded continuously before, during, and after a 2-minute period of isometric exercise (40% maximum voluntary contraction of the forearm). RESULTS: During the 2-minute isometric exercise, heart rate increased from 74+/-6 beats/min (mean +/- SEM) to 93+/-6 beats/min (P<0.005) and systolic and diastolic arterial blood pressure increased from 125+/-6 to 169+/-8 mm Hg (P<0.005) and from 65+/-3 to 96+/-5 mm Hg (P<0.005), respectively. IOP increased from 15+/-1 mm Hg at rest to 19+/-2 mm Hg at the end of the isometric exercise (P<0.005). CONCLUSIONS: During isometric exercise, IOP increased continuously, as long as the isometric exercise persisted, in parallel to the increase in systemic blood pressure.